src/HOL/Num.thy
author wenzelm
Sat May 25 15:37:53 2013 +0200 (2013-05-25)
changeset 52143 36ffe23b25f8
parent 51143 0a2371e7ced3
child 52187 1f7b3aadec69
permissions -rw-r--r--
syntax translations always depend on context;
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(*  Title:      HOL/Num.thy
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    Author:     Florian Haftmann
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    Author:     Brian Huffman
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*)
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header {* Binary Numerals *}
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theory Num
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imports Datatype
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begin
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subsection {* The @{text num} type *}
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datatype num = One | Bit0 num | Bit1 num
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text {* Increment function for type @{typ num} *}
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primrec inc :: "num \<Rightarrow> num" where
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  "inc One = Bit0 One" |
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  "inc (Bit0 x) = Bit1 x" |
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  "inc (Bit1 x) = Bit0 (inc x)"
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text {* Converting between type @{typ num} and type @{typ nat} *}
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primrec nat_of_num :: "num \<Rightarrow> nat" where
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  "nat_of_num One = Suc 0" |
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  "nat_of_num (Bit0 x) = nat_of_num x + nat_of_num x" |
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  "nat_of_num (Bit1 x) = Suc (nat_of_num x + nat_of_num x)"
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primrec num_of_nat :: "nat \<Rightarrow> num" where
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  "num_of_nat 0 = One" |
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  "num_of_nat (Suc n) = (if 0 < n then inc (num_of_nat n) else One)"
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lemma nat_of_num_pos: "0 < nat_of_num x"
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  by (induct x) simp_all
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lemma nat_of_num_neq_0: " nat_of_num x \<noteq> 0"
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  by (induct x) simp_all
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lemma nat_of_num_inc: "nat_of_num (inc x) = Suc (nat_of_num x)"
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  by (induct x) simp_all
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lemma num_of_nat_double:
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  "0 < n \<Longrightarrow> num_of_nat (n + n) = Bit0 (num_of_nat n)"
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  by (induct n) simp_all
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text {*
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  Type @{typ num} is isomorphic to the strictly positive
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  natural numbers.
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*}
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lemma nat_of_num_inverse: "num_of_nat (nat_of_num x) = x"
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  by (induct x) (simp_all add: num_of_nat_double nat_of_num_pos)
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lemma num_of_nat_inverse: "0 < n \<Longrightarrow> nat_of_num (num_of_nat n) = n"
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  by (induct n) (simp_all add: nat_of_num_inc)
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lemma num_eq_iff: "x = y \<longleftrightarrow> nat_of_num x = nat_of_num y"
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  apply safe
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  apply (drule arg_cong [where f=num_of_nat])
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  apply (simp add: nat_of_num_inverse)
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  done
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lemma num_induct [case_names One inc]:
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  fixes P :: "num \<Rightarrow> bool"
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  assumes One: "P One"
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    and inc: "\<And>x. P x \<Longrightarrow> P (inc x)"
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  shows "P x"
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proof -
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  obtain n where n: "Suc n = nat_of_num x"
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    by (cases "nat_of_num x", simp_all add: nat_of_num_neq_0)
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  have "P (num_of_nat (Suc n))"
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  proof (induct n)
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    case 0 show ?case using One by simp
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  next
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    case (Suc n)
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    then have "P (inc (num_of_nat (Suc n)))" by (rule inc)
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    then show "P (num_of_nat (Suc (Suc n)))" by simp
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  qed
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  with n show "P x"
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    by (simp add: nat_of_num_inverse)
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qed
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text {*
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  From now on, there are two possible models for @{typ num}:
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  as positive naturals (rule @{text "num_induct"})
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  and as digit representation (rules @{text "num.induct"}, @{text "num.cases"}).
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*}
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subsection {* Numeral operations *}
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instantiation num :: "{plus,times,linorder}"
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begin
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definition [code del]:
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  "m + n = num_of_nat (nat_of_num m + nat_of_num n)"
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definition [code del]:
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  "m * n = num_of_nat (nat_of_num m * nat_of_num n)"
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definition [code del]:
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  "m \<le> n \<longleftrightarrow> nat_of_num m \<le> nat_of_num n"
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definition [code del]:
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  "m < n \<longleftrightarrow> nat_of_num m < nat_of_num n"
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instance
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  by (default, auto simp add: less_num_def less_eq_num_def num_eq_iff)
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end
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lemma nat_of_num_add: "nat_of_num (x + y) = nat_of_num x + nat_of_num y"
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  unfolding plus_num_def
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  by (intro num_of_nat_inverse add_pos_pos nat_of_num_pos)
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lemma nat_of_num_mult: "nat_of_num (x * y) = nat_of_num x * nat_of_num y"
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  unfolding times_num_def
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  by (intro num_of_nat_inverse mult_pos_pos nat_of_num_pos)
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lemma add_num_simps [simp, code]:
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  "One + One = Bit0 One"
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  "One + Bit0 n = Bit1 n"
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  "One + Bit1 n = Bit0 (n + One)"
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  "Bit0 m + One = Bit1 m"
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  "Bit0 m + Bit0 n = Bit0 (m + n)"
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  "Bit0 m + Bit1 n = Bit1 (m + n)"
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  "Bit1 m + One = Bit0 (m + One)"
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  "Bit1 m + Bit0 n = Bit1 (m + n)"
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  "Bit1 m + Bit1 n = Bit0 (m + n + One)"
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  by (simp_all add: num_eq_iff nat_of_num_add)
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lemma mult_num_simps [simp, code]:
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  "m * One = m"
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  "One * n = n"
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  "Bit0 m * Bit0 n = Bit0 (Bit0 (m * n))"
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  "Bit0 m * Bit1 n = Bit0 (m * Bit1 n)"
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  "Bit1 m * Bit0 n = Bit0 (Bit1 m * n)"
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  "Bit1 m * Bit1 n = Bit1 (m + n + Bit0 (m * n))"
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  by (simp_all add: num_eq_iff nat_of_num_add
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    nat_of_num_mult distrib_right distrib_left)
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lemma eq_num_simps:
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  "One = One \<longleftrightarrow> True"
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  "One = Bit0 n \<longleftrightarrow> False"
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  "One = Bit1 n \<longleftrightarrow> False"
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  "Bit0 m = One \<longleftrightarrow> False"
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  "Bit1 m = One \<longleftrightarrow> False"
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  "Bit0 m = Bit0 n \<longleftrightarrow> m = n"
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  "Bit0 m = Bit1 n \<longleftrightarrow> False"
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  "Bit1 m = Bit0 n \<longleftrightarrow> False"
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  "Bit1 m = Bit1 n \<longleftrightarrow> m = n"
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  by simp_all
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lemma le_num_simps [simp, code]:
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  "One \<le> n \<longleftrightarrow> True"
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  "Bit0 m \<le> One \<longleftrightarrow> False"
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  "Bit1 m \<le> One \<longleftrightarrow> False"
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  "Bit0 m \<le> Bit0 n \<longleftrightarrow> m \<le> n"
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  "Bit0 m \<le> Bit1 n \<longleftrightarrow> m \<le> n"
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  "Bit1 m \<le> Bit1 n \<longleftrightarrow> m \<le> n"
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  "Bit1 m \<le> Bit0 n \<longleftrightarrow> m < n"
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  using nat_of_num_pos [of n] nat_of_num_pos [of m]
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  by (auto simp add: less_eq_num_def less_num_def)
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lemma less_num_simps [simp, code]:
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  "m < One \<longleftrightarrow> False"
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  "One < Bit0 n \<longleftrightarrow> True"
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  "One < Bit1 n \<longleftrightarrow> True"
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  "Bit0 m < Bit0 n \<longleftrightarrow> m < n"
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  "Bit0 m < Bit1 n \<longleftrightarrow> m \<le> n"
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  "Bit1 m < Bit1 n \<longleftrightarrow> m < n"
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  "Bit1 m < Bit0 n \<longleftrightarrow> m < n"
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  using nat_of_num_pos [of n] nat_of_num_pos [of m]
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  by (auto simp add: less_eq_num_def less_num_def)
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text {* Rules using @{text One} and @{text inc} as constructors *}
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lemma add_One: "x + One = inc x"
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  by (simp add: num_eq_iff nat_of_num_add nat_of_num_inc)
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lemma add_One_commute: "One + n = n + One"
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  by (induct n) simp_all
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lemma add_inc: "x + inc y = inc (x + y)"
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  by (simp add: num_eq_iff nat_of_num_add nat_of_num_inc)
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lemma mult_inc: "x * inc y = x * y + x"
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  by (simp add: num_eq_iff nat_of_num_mult nat_of_num_add nat_of_num_inc)
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text {* The @{const num_of_nat} conversion *}
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lemma num_of_nat_One:
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  "n \<le> 1 \<Longrightarrow> num_of_nat n = One"
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  by (cases n) simp_all
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lemma num_of_nat_plus_distrib:
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  "0 < m \<Longrightarrow> 0 < n \<Longrightarrow> num_of_nat (m + n) = num_of_nat m + num_of_nat n"
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  by (induct n) (auto simp add: add_One add_One_commute add_inc)
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text {* A double-and-decrement function *}
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primrec BitM :: "num \<Rightarrow> num" where
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  "BitM One = One" |
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  "BitM (Bit0 n) = Bit1 (BitM n)" |
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  "BitM (Bit1 n) = Bit1 (Bit0 n)"
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lemma BitM_plus_one: "BitM n + One = Bit0 n"
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  by (induct n) simp_all
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lemma one_plus_BitM: "One + BitM n = Bit0 n"
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  unfolding add_One_commute BitM_plus_one ..
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text {* Squaring and exponentiation *}
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primrec sqr :: "num \<Rightarrow> num" where
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  "sqr One = One" |
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  "sqr (Bit0 n) = Bit0 (Bit0 (sqr n))" |
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  "sqr (Bit1 n) = Bit1 (Bit0 (sqr n + n))"
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primrec pow :: "num \<Rightarrow> num \<Rightarrow> num" where
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  "pow x One = x" |
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  "pow x (Bit0 y) = sqr (pow x y)" |
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  "pow x (Bit1 y) = sqr (pow x y) * x"
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lemma nat_of_num_sqr: "nat_of_num (sqr x) = nat_of_num x * nat_of_num x"
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  by (induct x, simp_all add: algebra_simps nat_of_num_add)
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lemma sqr_conv_mult: "sqr x = x * x"
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  by (simp add: num_eq_iff nat_of_num_sqr nat_of_num_mult)
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subsection {* Binary numerals *}
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text {*
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  We embed binary representations into a generic algebraic
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  structure using @{text numeral}.
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*}
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class numeral = one + semigroup_add
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begin
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primrec numeral :: "num \<Rightarrow> 'a" where
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  numeral_One: "numeral One = 1" |
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  numeral_Bit0: "numeral (Bit0 n) = numeral n + numeral n" |
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  numeral_Bit1: "numeral (Bit1 n) = numeral n + numeral n + 1"
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lemma numeral_code [code]:
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  "numeral One = 1"
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  "numeral (Bit0 n) = (let m = numeral n in m + m)"
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  "numeral (Bit1 n) = (let m = numeral n in m + m + 1)"
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  by (simp_all add: Let_def)
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lemma one_plus_numeral_commute: "1 + numeral x = numeral x + 1"
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  apply (induct x)
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  apply simp
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  apply (simp add: add_assoc [symmetric], simp add: add_assoc)
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  apply (simp add: add_assoc [symmetric], simp add: add_assoc)
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  done
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lemma numeral_inc: "numeral (inc x) = numeral x + 1"
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proof (induct x)
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  case (Bit1 x)
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  have "numeral x + (1 + numeral x) + 1 = numeral x + (numeral x + 1) + 1"
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    by (simp only: one_plus_numeral_commute)
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  with Bit1 show ?case
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    by (simp add: add_assoc)
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qed simp_all
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declare numeral.simps [simp del]
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abbreviation "Numeral1 \<equiv> numeral One"
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declare numeral_One [code_post]
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end
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text {* Negative numerals. *}
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class neg_numeral = numeral + group_add
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begin
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definition neg_numeral :: "num \<Rightarrow> 'a" where
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  "neg_numeral k = - numeral k"
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end
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text {* Numeral syntax. *}
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syntax
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  "_Numeral" :: "num_const \<Rightarrow> 'a"    ("_")
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parse_translation {*
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  let
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    fun num_of_int n =
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      if n > 0 then
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        (case IntInf.quotRem (n, 2) of
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          (0, 1) => Syntax.const @{const_name One}
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        | (n, 0) => Syntax.const @{const_name Bit0} $ num_of_int n
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        | (n, 1) => Syntax.const @{const_name Bit1} $ num_of_int n)
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      else raise Match
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    val pos = Syntax.const @{const_name numeral}
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    val neg = Syntax.const @{const_name neg_numeral}
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    val one = Syntax.const @{const_name Groups.one}
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    val zero = Syntax.const @{const_name Groups.zero}
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    fun numeral_tr [(c as Const (@{syntax_const "_constrain"}, _)) $ t $ u] =
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          c $ numeral_tr [t] $ u
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      | numeral_tr [Const (num, _)] =
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          let
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            val {value, ...} = Lexicon.read_xnum num;
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          in
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            if value = 0 then zero else
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            if value > 0
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            then pos $ num_of_int value
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            else neg $ num_of_int (~value)
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          end
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      | numeral_tr ts = raise TERM ("numeral_tr", ts);
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  in [("_Numeral", K numeral_tr)] end
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*}
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typed_print_translation {*
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  let
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    fun dest_num (Const (@{const_syntax Bit0}, _) $ n) = 2 * dest_num n
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      | dest_num (Const (@{const_syntax Bit1}, _) $ n) = 2 * dest_num n + 1
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      | dest_num (Const (@{const_syntax One}, _)) = 1;
wenzelm@52143
   326
    fun num_tr' sign ctxt T [n] =
wenzelm@52143
   327
      let
wenzelm@52143
   328
        val k = dest_num n;
wenzelm@52143
   329
        val t' = Syntax.const @{syntax_const "_Numeral"} $
wenzelm@52143
   330
          Syntax.free (sign ^ string_of_int k);
wenzelm@52143
   331
      in
wenzelm@52143
   332
        (case T of
wenzelm@52143
   333
          Type (@{type_name fun}, [_, T']) =>
wenzelm@52143
   334
            if not (Printer.show_type_constraint ctxt) andalso can Term.dest_Type T' then t'
wenzelm@52143
   335
            else Syntax.const @{syntax_const "_constrain"} $ t' $ Syntax_Phases.term_of_typ ctxt T'
wenzelm@52143
   336
        | T' => if T' = dummyT then t' else raise Match)
wenzelm@52143
   337
      end;
wenzelm@52143
   338
  in
wenzelm@52143
   339
   [(@{const_syntax numeral}, num_tr' ""),
wenzelm@52143
   340
    (@{const_syntax neg_numeral}, num_tr' "-")]
wenzelm@52143
   341
  end
huffman@47108
   342
*}
huffman@47108
   343
wenzelm@48891
   344
ML_file "Tools/numeral.ML"
huffman@47228
   345
huffman@47228
   346
huffman@47108
   347
subsection {* Class-specific numeral rules *}
huffman@47108
   348
huffman@47108
   349
text {*
huffman@47108
   350
  @{const numeral} is a morphism.
huffman@47108
   351
*}
huffman@47108
   352
huffman@47108
   353
subsubsection {* Structures with addition: class @{text numeral} *}
huffman@47108
   354
huffman@47108
   355
context numeral
huffman@47108
   356
begin
huffman@47108
   357
huffman@47108
   358
lemma numeral_add: "numeral (m + n) = numeral m + numeral n"
huffman@47108
   359
  by (induct n rule: num_induct)
huffman@47108
   360
     (simp_all only: numeral_One add_One add_inc numeral_inc add_assoc)
huffman@47108
   361
huffman@47108
   362
lemma numeral_plus_numeral: "numeral m + numeral n = numeral (m + n)"
huffman@47108
   363
  by (rule numeral_add [symmetric])
huffman@47108
   364
huffman@47108
   365
lemma numeral_plus_one: "numeral n + 1 = numeral (n + One)"
huffman@47108
   366
  using numeral_add [of n One] by (simp add: numeral_One)
huffman@47108
   367
huffman@47108
   368
lemma one_plus_numeral: "1 + numeral n = numeral (One + n)"
huffman@47108
   369
  using numeral_add [of One n] by (simp add: numeral_One)
huffman@47108
   370
huffman@47108
   371
lemma one_add_one: "1 + 1 = 2"
huffman@47108
   372
  using numeral_add [of One One] by (simp add: numeral_One)
huffman@47108
   373
huffman@47108
   374
lemmas add_numeral_special =
huffman@47108
   375
  numeral_plus_one one_plus_numeral one_add_one
huffman@47108
   376
huffman@47108
   377
end
huffman@47108
   378
huffman@47108
   379
subsubsection {*
huffman@47108
   380
  Structures with negation: class @{text neg_numeral}
huffman@47108
   381
*}
huffman@47108
   382
huffman@47108
   383
context neg_numeral
huffman@47108
   384
begin
huffman@47108
   385
huffman@47108
   386
text {* Numerals form an abelian subgroup. *}
huffman@47108
   387
huffman@47108
   388
inductive is_num :: "'a \<Rightarrow> bool" where
huffman@47108
   389
  "is_num 1" |
huffman@47108
   390
  "is_num x \<Longrightarrow> is_num (- x)" |
huffman@47108
   391
  "\<lbrakk>is_num x; is_num y\<rbrakk> \<Longrightarrow> is_num (x + y)"
huffman@47108
   392
huffman@47108
   393
lemma is_num_numeral: "is_num (numeral k)"
huffman@47108
   394
  by (induct k, simp_all add: numeral.simps is_num.intros)
huffman@47108
   395
huffman@47108
   396
lemma is_num_add_commute:
huffman@47108
   397
  "\<lbrakk>is_num x; is_num y\<rbrakk> \<Longrightarrow> x + y = y + x"
huffman@47108
   398
  apply (induct x rule: is_num.induct)
huffman@47108
   399
  apply (induct y rule: is_num.induct)
huffman@47108
   400
  apply simp
huffman@47108
   401
  apply (rule_tac a=x in add_left_imp_eq)
huffman@47108
   402
  apply (rule_tac a=x in add_right_imp_eq)
huffman@47108
   403
  apply (simp add: add_assoc minus_add_cancel)
huffman@47108
   404
  apply (simp add: add_assoc [symmetric], simp add: add_assoc)
huffman@47108
   405
  apply (rule_tac a=x in add_left_imp_eq)
huffman@47108
   406
  apply (rule_tac a=x in add_right_imp_eq)
huffman@47108
   407
  apply (simp add: add_assoc minus_add_cancel add_minus_cancel)
huffman@47108
   408
  apply (simp add: add_assoc, simp add: add_assoc [symmetric])
huffman@47108
   409
  done
huffman@47108
   410
huffman@47108
   411
lemma is_num_add_left_commute:
huffman@47108
   412
  "\<lbrakk>is_num x; is_num y\<rbrakk> \<Longrightarrow> x + (y + z) = y + (x + z)"
huffman@47108
   413
  by (simp only: add_assoc [symmetric] is_num_add_commute)
huffman@47108
   414
huffman@47108
   415
lemmas is_num_normalize =
huffman@47108
   416
  add_assoc is_num_add_commute is_num_add_left_commute
huffman@47108
   417
  is_num.intros is_num_numeral
huffman@47108
   418
  diff_minus minus_add add_minus_cancel minus_add_cancel
huffman@47108
   419
huffman@47108
   420
definition dbl :: "'a \<Rightarrow> 'a" where "dbl x = x + x"
huffman@47108
   421
definition dbl_inc :: "'a \<Rightarrow> 'a" where "dbl_inc x = x + x + 1"
huffman@47108
   422
definition dbl_dec :: "'a \<Rightarrow> 'a" where "dbl_dec x = x + x - 1"
huffman@47108
   423
huffman@47108
   424
definition sub :: "num \<Rightarrow> num \<Rightarrow> 'a" where
huffman@47108
   425
  "sub k l = numeral k - numeral l"
huffman@47108
   426
huffman@47108
   427
lemma numeral_BitM: "numeral (BitM n) = numeral (Bit0 n) - 1"
huffman@47108
   428
  by (simp only: BitM_plus_one [symmetric] numeral_add numeral_One eq_diff_eq)
huffman@47108
   429
huffman@47108
   430
lemma dbl_simps [simp]:
huffman@47108
   431
  "dbl (neg_numeral k) = neg_numeral (Bit0 k)"
huffman@47108
   432
  "dbl 0 = 0"
huffman@47108
   433
  "dbl 1 = 2"
huffman@47108
   434
  "dbl (numeral k) = numeral (Bit0 k)"
huffman@47108
   435
  unfolding dbl_def neg_numeral_def numeral.simps
huffman@47108
   436
  by (simp_all add: minus_add)
huffman@47108
   437
huffman@47108
   438
lemma dbl_inc_simps [simp]:
huffman@47108
   439
  "dbl_inc (neg_numeral k) = neg_numeral (BitM k)"
huffman@47108
   440
  "dbl_inc 0 = 1"
huffman@47108
   441
  "dbl_inc 1 = 3"
huffman@47108
   442
  "dbl_inc (numeral k) = numeral (Bit1 k)"
huffman@47108
   443
  unfolding dbl_inc_def neg_numeral_def numeral.simps numeral_BitM
huffman@47108
   444
  by (simp_all add: is_num_normalize)
huffman@47108
   445
huffman@47108
   446
lemma dbl_dec_simps [simp]:
huffman@47108
   447
  "dbl_dec (neg_numeral k) = neg_numeral (Bit1 k)"
huffman@47108
   448
  "dbl_dec 0 = -1"
huffman@47108
   449
  "dbl_dec 1 = 1"
huffman@47108
   450
  "dbl_dec (numeral k) = numeral (BitM k)"
huffman@47108
   451
  unfolding dbl_dec_def neg_numeral_def numeral.simps numeral_BitM
huffman@47108
   452
  by (simp_all add: is_num_normalize)
huffman@47108
   453
huffman@47108
   454
lemma sub_num_simps [simp]:
huffman@47108
   455
  "sub One One = 0"
huffman@47108
   456
  "sub One (Bit0 l) = neg_numeral (BitM l)"
huffman@47108
   457
  "sub One (Bit1 l) = neg_numeral (Bit0 l)"
huffman@47108
   458
  "sub (Bit0 k) One = numeral (BitM k)"
huffman@47108
   459
  "sub (Bit1 k) One = numeral (Bit0 k)"
huffman@47108
   460
  "sub (Bit0 k) (Bit0 l) = dbl (sub k l)"
huffman@47108
   461
  "sub (Bit0 k) (Bit1 l) = dbl_dec (sub k l)"
huffman@47108
   462
  "sub (Bit1 k) (Bit0 l) = dbl_inc (sub k l)"
huffman@47108
   463
  "sub (Bit1 k) (Bit1 l) = dbl (sub k l)"
huffman@47108
   464
  unfolding dbl_def dbl_dec_def dbl_inc_def sub_def
huffman@47108
   465
  unfolding neg_numeral_def numeral.simps numeral_BitM
huffman@47108
   466
  by (simp_all add: is_num_normalize)
huffman@47108
   467
huffman@47108
   468
lemma add_neg_numeral_simps:
huffman@47108
   469
  "numeral m + neg_numeral n = sub m n"
huffman@47108
   470
  "neg_numeral m + numeral n = sub n m"
huffman@47108
   471
  "neg_numeral m + neg_numeral n = neg_numeral (m + n)"
huffman@47108
   472
  unfolding sub_def diff_minus neg_numeral_def numeral_add numeral.simps
huffman@47108
   473
  by (simp_all add: is_num_normalize)
huffman@47108
   474
huffman@47108
   475
lemma add_neg_numeral_special:
huffman@47108
   476
  "1 + neg_numeral m = sub One m"
huffman@47108
   477
  "neg_numeral m + 1 = sub One m"
huffman@47108
   478
  unfolding sub_def diff_minus neg_numeral_def numeral_add numeral.simps
huffman@47108
   479
  by (simp_all add: is_num_normalize)
huffman@47108
   480
huffman@47108
   481
lemma diff_numeral_simps:
huffman@47108
   482
  "numeral m - numeral n = sub m n"
huffman@47108
   483
  "numeral m - neg_numeral n = numeral (m + n)"
huffman@47108
   484
  "neg_numeral m - numeral n = neg_numeral (m + n)"
huffman@47108
   485
  "neg_numeral m - neg_numeral n = sub n m"
huffman@47108
   486
  unfolding neg_numeral_def sub_def diff_minus numeral_add numeral.simps
huffman@47108
   487
  by (simp_all add: is_num_normalize)
huffman@47108
   488
huffman@47108
   489
lemma diff_numeral_special:
huffman@47108
   490
  "1 - numeral n = sub One n"
huffman@47108
   491
  "1 - neg_numeral n = numeral (One + n)"
huffman@47108
   492
  "numeral m - 1 = sub m One"
huffman@47108
   493
  "neg_numeral m - 1 = neg_numeral (m + One)"
huffman@47108
   494
  unfolding neg_numeral_def sub_def diff_minus numeral_add numeral.simps
huffman@47108
   495
  by (simp_all add: is_num_normalize)
huffman@47108
   496
huffman@47108
   497
lemma minus_one: "- 1 = -1"
huffman@47108
   498
  unfolding neg_numeral_def numeral.simps ..
huffman@47108
   499
huffman@47108
   500
lemma minus_numeral: "- numeral n = neg_numeral n"
huffman@47108
   501
  unfolding neg_numeral_def ..
huffman@47108
   502
huffman@47108
   503
lemma minus_neg_numeral: "- neg_numeral n = numeral n"
huffman@47108
   504
  unfolding neg_numeral_def by simp
huffman@47108
   505
huffman@47108
   506
lemmas minus_numeral_simps [simp] =
huffman@47108
   507
  minus_one minus_numeral minus_neg_numeral
huffman@47108
   508
huffman@47108
   509
end
huffman@47108
   510
huffman@47108
   511
subsubsection {*
huffman@47108
   512
  Structures with multiplication: class @{text semiring_numeral}
huffman@47108
   513
*}
huffman@47108
   514
huffman@47108
   515
class semiring_numeral = semiring + monoid_mult
huffman@47108
   516
begin
huffman@47108
   517
huffman@47108
   518
subclass numeral ..
huffman@47108
   519
huffman@47108
   520
lemma numeral_mult: "numeral (m * n) = numeral m * numeral n"
huffman@47108
   521
  apply (induct n rule: num_induct)
huffman@47108
   522
  apply (simp add: numeral_One)
webertj@49962
   523
  apply (simp add: mult_inc numeral_inc numeral_add distrib_left)
huffman@47108
   524
  done
huffman@47108
   525
huffman@47108
   526
lemma numeral_times_numeral: "numeral m * numeral n = numeral (m * n)"
huffman@47108
   527
  by (rule numeral_mult [symmetric])
huffman@47108
   528
huffman@47108
   529
end
huffman@47108
   530
huffman@47108
   531
subsubsection {*
huffman@47108
   532
  Structures with a zero: class @{text semiring_1}
huffman@47108
   533
*}
huffman@47108
   534
huffman@47108
   535
context semiring_1
huffman@47108
   536
begin
huffman@47108
   537
huffman@47108
   538
subclass semiring_numeral ..
huffman@47108
   539
huffman@47108
   540
lemma of_nat_numeral [simp]: "of_nat (numeral n) = numeral n"
huffman@47108
   541
  by (induct n,
huffman@47108
   542
    simp_all only: numeral.simps numeral_class.numeral.simps of_nat_add of_nat_1)
huffman@47108
   543
huffman@47192
   544
lemma mult_2: "2 * z = z + z"
webertj@49962
   545
  unfolding one_add_one [symmetric] distrib_right by simp
huffman@47192
   546
huffman@47192
   547
lemma mult_2_right: "z * 2 = z + z"
webertj@49962
   548
  unfolding one_add_one [symmetric] distrib_left by simp
huffman@47192
   549
huffman@47108
   550
end
huffman@47108
   551
haftmann@51143
   552
lemma nat_of_num_numeral [code_abbrev]:
haftmann@51143
   553
  "nat_of_num = numeral"
huffman@47108
   554
proof
huffman@47108
   555
  fix n
huffman@47108
   556
  have "numeral n = nat_of_num n"
huffman@47108
   557
    by (induct n) (simp_all add: numeral.simps)
huffman@47108
   558
  then show "nat_of_num n = numeral n" by simp
huffman@47108
   559
qed
huffman@47108
   560
haftmann@51143
   561
lemma nat_of_num_code [code]:
haftmann@51143
   562
  "nat_of_num One = 1"
haftmann@51143
   563
  "nat_of_num (Bit0 n) = (let m = nat_of_num n in m + m)"
haftmann@51143
   564
  "nat_of_num (Bit1 n) = (let m = nat_of_num n in Suc (m + m))"
haftmann@51143
   565
  by (simp_all add: Let_def)
haftmann@51143
   566
huffman@47108
   567
subsubsection {*
huffman@47108
   568
  Equality: class @{text semiring_char_0}
huffman@47108
   569
*}
huffman@47108
   570
huffman@47108
   571
context semiring_char_0
huffman@47108
   572
begin
huffman@47108
   573
huffman@47108
   574
lemma numeral_eq_iff: "numeral m = numeral n \<longleftrightarrow> m = n"
huffman@47108
   575
  unfolding of_nat_numeral [symmetric] nat_of_num_numeral [symmetric]
huffman@47108
   576
    of_nat_eq_iff num_eq_iff ..
huffman@47108
   577
huffman@47108
   578
lemma numeral_eq_one_iff: "numeral n = 1 \<longleftrightarrow> n = One"
huffman@47108
   579
  by (rule numeral_eq_iff [of n One, unfolded numeral_One])
huffman@47108
   580
huffman@47108
   581
lemma one_eq_numeral_iff: "1 = numeral n \<longleftrightarrow> One = n"
huffman@47108
   582
  by (rule numeral_eq_iff [of One n, unfolded numeral_One])
huffman@47108
   583
huffman@47108
   584
lemma numeral_neq_zero: "numeral n \<noteq> 0"
huffman@47108
   585
  unfolding of_nat_numeral [symmetric] nat_of_num_numeral [symmetric]
huffman@47108
   586
  by (simp add: nat_of_num_pos)
huffman@47108
   587
huffman@47108
   588
lemma zero_neq_numeral: "0 \<noteq> numeral n"
huffman@47108
   589
  unfolding eq_commute [of 0] by (rule numeral_neq_zero)
huffman@47108
   590
huffman@47108
   591
lemmas eq_numeral_simps [simp] =
huffman@47108
   592
  numeral_eq_iff
huffman@47108
   593
  numeral_eq_one_iff
huffman@47108
   594
  one_eq_numeral_iff
huffman@47108
   595
  numeral_neq_zero
huffman@47108
   596
  zero_neq_numeral
huffman@47108
   597
huffman@47108
   598
end
huffman@47108
   599
huffman@47108
   600
subsubsection {*
huffman@47108
   601
  Comparisons: class @{text linordered_semidom}
huffman@47108
   602
*}
huffman@47108
   603
huffman@47108
   604
text {*  Could be perhaps more general than here. *}
huffman@47108
   605
huffman@47108
   606
context linordered_semidom
huffman@47108
   607
begin
huffman@47108
   608
huffman@47108
   609
lemma numeral_le_iff: "numeral m \<le> numeral n \<longleftrightarrow> m \<le> n"
huffman@47108
   610
proof -
huffman@47108
   611
  have "of_nat (numeral m) \<le> of_nat (numeral n) \<longleftrightarrow> m \<le> n"
huffman@47108
   612
    unfolding less_eq_num_def nat_of_num_numeral of_nat_le_iff ..
huffman@47108
   613
  then show ?thesis by simp
huffman@47108
   614
qed
huffman@47108
   615
huffman@47108
   616
lemma one_le_numeral: "1 \<le> numeral n"
huffman@47108
   617
using numeral_le_iff [of One n] by (simp add: numeral_One)
huffman@47108
   618
huffman@47108
   619
lemma numeral_le_one_iff: "numeral n \<le> 1 \<longleftrightarrow> n \<le> One"
huffman@47108
   620
using numeral_le_iff [of n One] by (simp add: numeral_One)
huffman@47108
   621
huffman@47108
   622
lemma numeral_less_iff: "numeral m < numeral n \<longleftrightarrow> m < n"
huffman@47108
   623
proof -
huffman@47108
   624
  have "of_nat (numeral m) < of_nat (numeral n) \<longleftrightarrow> m < n"
huffman@47108
   625
    unfolding less_num_def nat_of_num_numeral of_nat_less_iff ..
huffman@47108
   626
  then show ?thesis by simp
huffman@47108
   627
qed
huffman@47108
   628
huffman@47108
   629
lemma not_numeral_less_one: "\<not> numeral n < 1"
huffman@47108
   630
  using numeral_less_iff [of n One] by (simp add: numeral_One)
huffman@47108
   631
huffman@47108
   632
lemma one_less_numeral_iff: "1 < numeral n \<longleftrightarrow> One < n"
huffman@47108
   633
  using numeral_less_iff [of One n] by (simp add: numeral_One)
huffman@47108
   634
huffman@47108
   635
lemma zero_le_numeral: "0 \<le> numeral n"
huffman@47108
   636
  by (induct n) (simp_all add: numeral.simps)
huffman@47108
   637
huffman@47108
   638
lemma zero_less_numeral: "0 < numeral n"
huffman@47108
   639
  by (induct n) (simp_all add: numeral.simps add_pos_pos)
huffman@47108
   640
huffman@47108
   641
lemma not_numeral_le_zero: "\<not> numeral n \<le> 0"
huffman@47108
   642
  by (simp add: not_le zero_less_numeral)
huffman@47108
   643
huffman@47108
   644
lemma not_numeral_less_zero: "\<not> numeral n < 0"
huffman@47108
   645
  by (simp add: not_less zero_le_numeral)
huffman@47108
   646
huffman@47108
   647
lemmas le_numeral_extra =
huffman@47108
   648
  zero_le_one not_one_le_zero
huffman@47108
   649
  order_refl [of 0] order_refl [of 1]
huffman@47108
   650
huffman@47108
   651
lemmas less_numeral_extra =
huffman@47108
   652
  zero_less_one not_one_less_zero
huffman@47108
   653
  less_irrefl [of 0] less_irrefl [of 1]
huffman@47108
   654
huffman@47108
   655
lemmas le_numeral_simps [simp] =
huffman@47108
   656
  numeral_le_iff
huffman@47108
   657
  one_le_numeral
huffman@47108
   658
  numeral_le_one_iff
huffman@47108
   659
  zero_le_numeral
huffman@47108
   660
  not_numeral_le_zero
huffman@47108
   661
huffman@47108
   662
lemmas less_numeral_simps [simp] =
huffman@47108
   663
  numeral_less_iff
huffman@47108
   664
  one_less_numeral_iff
huffman@47108
   665
  not_numeral_less_one
huffman@47108
   666
  zero_less_numeral
huffman@47108
   667
  not_numeral_less_zero
huffman@47108
   668
huffman@47108
   669
end
huffman@47108
   670
huffman@47108
   671
subsubsection {*
huffman@47108
   672
  Multiplication and negation: class @{text ring_1}
huffman@47108
   673
*}
huffman@47108
   674
huffman@47108
   675
context ring_1
huffman@47108
   676
begin
huffman@47108
   677
huffman@47108
   678
subclass neg_numeral ..
huffman@47108
   679
huffman@47108
   680
lemma mult_neg_numeral_simps:
huffman@47108
   681
  "neg_numeral m * neg_numeral n = numeral (m * n)"
huffman@47108
   682
  "neg_numeral m * numeral n = neg_numeral (m * n)"
huffman@47108
   683
  "numeral m * neg_numeral n = neg_numeral (m * n)"
huffman@47108
   684
  unfolding neg_numeral_def mult_minus_left mult_minus_right
huffman@47108
   685
  by (simp_all only: minus_minus numeral_mult)
huffman@47108
   686
huffman@47108
   687
lemma mult_minus1 [simp]: "-1 * z = - z"
huffman@47108
   688
  unfolding neg_numeral_def numeral.simps mult_minus_left by simp
huffman@47108
   689
huffman@47108
   690
lemma mult_minus1_right [simp]: "z * -1 = - z"
huffman@47108
   691
  unfolding neg_numeral_def numeral.simps mult_minus_right by simp
huffman@47108
   692
huffman@47108
   693
end
huffman@47108
   694
huffman@47108
   695
subsubsection {*
huffman@47108
   696
  Equality using @{text iszero} for rings with non-zero characteristic
huffman@47108
   697
*}
huffman@47108
   698
huffman@47108
   699
context ring_1
huffman@47108
   700
begin
huffman@47108
   701
huffman@47108
   702
definition iszero :: "'a \<Rightarrow> bool"
huffman@47108
   703
  where "iszero z \<longleftrightarrow> z = 0"
huffman@47108
   704
huffman@47108
   705
lemma iszero_0 [simp]: "iszero 0"
huffman@47108
   706
  by (simp add: iszero_def)
huffman@47108
   707
huffman@47108
   708
lemma not_iszero_1 [simp]: "\<not> iszero 1"
huffman@47108
   709
  by (simp add: iszero_def)
huffman@47108
   710
huffman@47108
   711
lemma not_iszero_Numeral1: "\<not> iszero Numeral1"
huffman@47108
   712
  by (simp add: numeral_One)
huffman@47108
   713
huffman@47108
   714
lemma iszero_neg_numeral [simp]:
huffman@47108
   715
  "iszero (neg_numeral w) \<longleftrightarrow> iszero (numeral w)"
huffman@47108
   716
  unfolding iszero_def neg_numeral_def
huffman@47108
   717
  by (rule neg_equal_0_iff_equal)
huffman@47108
   718
huffman@47108
   719
lemma eq_iff_iszero_diff: "x = y \<longleftrightarrow> iszero (x - y)"
huffman@47108
   720
  unfolding iszero_def by (rule eq_iff_diff_eq_0)
huffman@47108
   721
huffman@47108
   722
text {* The @{text "eq_numeral_iff_iszero"} lemmas are not declared
huffman@47108
   723
@{text "[simp]"} by default, because for rings of characteristic zero,
huffman@47108
   724
better simp rules are possible. For a type like integers mod @{text
huffman@47108
   725
"n"}, type-instantiated versions of these rules should be added to the
huffman@47108
   726
simplifier, along with a type-specific rule for deciding propositions
huffman@47108
   727
of the form @{text "iszero (numeral w)"}.
huffman@47108
   728
huffman@47108
   729
bh: Maybe it would not be so bad to just declare these as simp
huffman@47108
   730
rules anyway? I should test whether these rules take precedence over
huffman@47108
   731
the @{text "ring_char_0"} rules in the simplifier.
huffman@47108
   732
*}
huffman@47108
   733
huffman@47108
   734
lemma eq_numeral_iff_iszero:
huffman@47108
   735
  "numeral x = numeral y \<longleftrightarrow> iszero (sub x y)"
huffman@47108
   736
  "numeral x = neg_numeral y \<longleftrightarrow> iszero (numeral (x + y))"
huffman@47108
   737
  "neg_numeral x = numeral y \<longleftrightarrow> iszero (numeral (x + y))"
huffman@47108
   738
  "neg_numeral x = neg_numeral y \<longleftrightarrow> iszero (sub y x)"
huffman@47108
   739
  "numeral x = 1 \<longleftrightarrow> iszero (sub x One)"
huffman@47108
   740
  "1 = numeral y \<longleftrightarrow> iszero (sub One y)"
huffman@47108
   741
  "neg_numeral x = 1 \<longleftrightarrow> iszero (numeral (x + One))"
huffman@47108
   742
  "1 = neg_numeral y \<longleftrightarrow> iszero (numeral (One + y))"
huffman@47108
   743
  "numeral x = 0 \<longleftrightarrow> iszero (numeral x)"
huffman@47108
   744
  "0 = numeral y \<longleftrightarrow> iszero (numeral y)"
huffman@47108
   745
  "neg_numeral x = 0 \<longleftrightarrow> iszero (numeral x)"
huffman@47108
   746
  "0 = neg_numeral y \<longleftrightarrow> iszero (numeral y)"
huffman@47108
   747
  unfolding eq_iff_iszero_diff diff_numeral_simps diff_numeral_special
huffman@47108
   748
  by simp_all
huffman@47108
   749
huffman@47108
   750
end
huffman@47108
   751
huffman@47108
   752
subsubsection {*
huffman@47108
   753
  Equality and negation: class @{text ring_char_0}
huffman@47108
   754
*}
huffman@47108
   755
huffman@47108
   756
class ring_char_0 = ring_1 + semiring_char_0
huffman@47108
   757
begin
huffman@47108
   758
huffman@47108
   759
lemma not_iszero_numeral [simp]: "\<not> iszero (numeral w)"
huffman@47108
   760
  by (simp add: iszero_def)
huffman@47108
   761
huffman@47108
   762
lemma neg_numeral_eq_iff: "neg_numeral m = neg_numeral n \<longleftrightarrow> m = n"
huffman@47108
   763
  by (simp only: neg_numeral_def neg_equal_iff_equal numeral_eq_iff)
huffman@47108
   764
huffman@47108
   765
lemma numeral_neq_neg_numeral: "numeral m \<noteq> neg_numeral n"
huffman@47108
   766
  unfolding neg_numeral_def eq_neg_iff_add_eq_0
huffman@47108
   767
  by (simp add: numeral_plus_numeral)
huffman@47108
   768
huffman@47108
   769
lemma neg_numeral_neq_numeral: "neg_numeral m \<noteq> numeral n"
huffman@47108
   770
  by (rule numeral_neq_neg_numeral [symmetric])
huffman@47108
   771
huffman@47108
   772
lemma zero_neq_neg_numeral: "0 \<noteq> neg_numeral n"
huffman@47108
   773
  unfolding neg_numeral_def neg_0_equal_iff_equal by simp
huffman@47108
   774
huffman@47108
   775
lemma neg_numeral_neq_zero: "neg_numeral n \<noteq> 0"
huffman@47108
   776
  unfolding neg_numeral_def neg_equal_0_iff_equal by simp
huffman@47108
   777
huffman@47108
   778
lemma one_neq_neg_numeral: "1 \<noteq> neg_numeral n"
huffman@47108
   779
  using numeral_neq_neg_numeral [of One n] by (simp add: numeral_One)
huffman@47108
   780
huffman@47108
   781
lemma neg_numeral_neq_one: "neg_numeral n \<noteq> 1"
huffman@47108
   782
  using neg_numeral_neq_numeral [of n One] by (simp add: numeral_One)
huffman@47108
   783
huffman@47108
   784
lemmas eq_neg_numeral_simps [simp] =
huffman@47108
   785
  neg_numeral_eq_iff
huffman@47108
   786
  numeral_neq_neg_numeral neg_numeral_neq_numeral
huffman@47108
   787
  one_neq_neg_numeral neg_numeral_neq_one
huffman@47108
   788
  zero_neq_neg_numeral neg_numeral_neq_zero
huffman@47108
   789
huffman@47108
   790
end
huffman@47108
   791
huffman@47108
   792
subsubsection {*
huffman@47108
   793
  Structures with negation and order: class @{text linordered_idom}
huffman@47108
   794
*}
huffman@47108
   795
huffman@47108
   796
context linordered_idom
huffman@47108
   797
begin
huffman@47108
   798
huffman@47108
   799
subclass ring_char_0 ..
huffman@47108
   800
huffman@47108
   801
lemma neg_numeral_le_iff: "neg_numeral m \<le> neg_numeral n \<longleftrightarrow> n \<le> m"
huffman@47108
   802
  by (simp only: neg_numeral_def neg_le_iff_le numeral_le_iff)
huffman@47108
   803
huffman@47108
   804
lemma neg_numeral_less_iff: "neg_numeral m < neg_numeral n \<longleftrightarrow> n < m"
huffman@47108
   805
  by (simp only: neg_numeral_def neg_less_iff_less numeral_less_iff)
huffman@47108
   806
huffman@47108
   807
lemma neg_numeral_less_zero: "neg_numeral n < 0"
huffman@47108
   808
  by (simp only: neg_numeral_def neg_less_0_iff_less zero_less_numeral)
huffman@47108
   809
huffman@47108
   810
lemma neg_numeral_le_zero: "neg_numeral n \<le> 0"
huffman@47108
   811
  by (simp only: neg_numeral_def neg_le_0_iff_le zero_le_numeral)
huffman@47108
   812
huffman@47108
   813
lemma not_zero_less_neg_numeral: "\<not> 0 < neg_numeral n"
huffman@47108
   814
  by (simp only: not_less neg_numeral_le_zero)
huffman@47108
   815
huffman@47108
   816
lemma not_zero_le_neg_numeral: "\<not> 0 \<le> neg_numeral n"
huffman@47108
   817
  by (simp only: not_le neg_numeral_less_zero)
huffman@47108
   818
huffman@47108
   819
lemma neg_numeral_less_numeral: "neg_numeral m < numeral n"
huffman@47108
   820
  using neg_numeral_less_zero zero_less_numeral by (rule less_trans)
huffman@47108
   821
huffman@47108
   822
lemma neg_numeral_le_numeral: "neg_numeral m \<le> numeral n"
huffman@47108
   823
  by (simp only: less_imp_le neg_numeral_less_numeral)
huffman@47108
   824
huffman@47108
   825
lemma not_numeral_less_neg_numeral: "\<not> numeral m < neg_numeral n"
huffman@47108
   826
  by (simp only: not_less neg_numeral_le_numeral)
huffman@47108
   827
huffman@47108
   828
lemma not_numeral_le_neg_numeral: "\<not> numeral m \<le> neg_numeral n"
huffman@47108
   829
  by (simp only: not_le neg_numeral_less_numeral)
huffman@47108
   830
  
huffman@47108
   831
lemma neg_numeral_less_one: "neg_numeral m < 1"
huffman@47108
   832
  by (rule neg_numeral_less_numeral [of m One, unfolded numeral_One])
huffman@47108
   833
huffman@47108
   834
lemma neg_numeral_le_one: "neg_numeral m \<le> 1"
huffman@47108
   835
  by (rule neg_numeral_le_numeral [of m One, unfolded numeral_One])
huffman@47108
   836
huffman@47108
   837
lemma not_one_less_neg_numeral: "\<not> 1 < neg_numeral m"
huffman@47108
   838
  by (simp only: not_less neg_numeral_le_one)
huffman@47108
   839
huffman@47108
   840
lemma not_one_le_neg_numeral: "\<not> 1 \<le> neg_numeral m"
huffman@47108
   841
  by (simp only: not_le neg_numeral_less_one)
huffman@47108
   842
huffman@47108
   843
lemma sub_non_negative:
huffman@47108
   844
  "sub n m \<ge> 0 \<longleftrightarrow> n \<ge> m"
huffman@47108
   845
  by (simp only: sub_def le_diff_eq) simp
huffman@47108
   846
huffman@47108
   847
lemma sub_positive:
huffman@47108
   848
  "sub n m > 0 \<longleftrightarrow> n > m"
huffman@47108
   849
  by (simp only: sub_def less_diff_eq) simp
huffman@47108
   850
huffman@47108
   851
lemma sub_non_positive:
huffman@47108
   852
  "sub n m \<le> 0 \<longleftrightarrow> n \<le> m"
huffman@47108
   853
  by (simp only: sub_def diff_le_eq) simp
huffman@47108
   854
huffman@47108
   855
lemma sub_negative:
huffman@47108
   856
  "sub n m < 0 \<longleftrightarrow> n < m"
huffman@47108
   857
  by (simp only: sub_def diff_less_eq) simp
huffman@47108
   858
huffman@47108
   859
lemmas le_neg_numeral_simps [simp] =
huffman@47108
   860
  neg_numeral_le_iff
huffman@47108
   861
  neg_numeral_le_numeral not_numeral_le_neg_numeral
huffman@47108
   862
  neg_numeral_le_zero not_zero_le_neg_numeral
huffman@47108
   863
  neg_numeral_le_one not_one_le_neg_numeral
huffman@47108
   864
huffman@47108
   865
lemmas less_neg_numeral_simps [simp] =
huffman@47108
   866
  neg_numeral_less_iff
huffman@47108
   867
  neg_numeral_less_numeral not_numeral_less_neg_numeral
huffman@47108
   868
  neg_numeral_less_zero not_zero_less_neg_numeral
huffman@47108
   869
  neg_numeral_less_one not_one_less_neg_numeral
huffman@47108
   870
huffman@47108
   871
lemma abs_numeral [simp]: "abs (numeral n) = numeral n"
huffman@47108
   872
  by simp
huffman@47108
   873
huffman@47108
   874
lemma abs_neg_numeral [simp]: "abs (neg_numeral n) = numeral n"
huffman@47108
   875
  by (simp only: neg_numeral_def abs_minus_cancel abs_numeral)
huffman@47108
   876
huffman@47108
   877
end
huffman@47108
   878
huffman@47108
   879
subsubsection {*
huffman@47108
   880
  Natural numbers
huffman@47108
   881
*}
huffman@47108
   882
huffman@47299
   883
lemma Suc_1 [simp]: "Suc 1 = 2"
huffman@47299
   884
  unfolding Suc_eq_plus1 by (rule one_add_one)
huffman@47299
   885
huffman@47108
   886
lemma Suc_numeral [simp]: "Suc (numeral n) = numeral (n + One)"
huffman@47299
   887
  unfolding Suc_eq_plus1 by (rule numeral_plus_one)
huffman@47108
   888
huffman@47209
   889
definition pred_numeral :: "num \<Rightarrow> nat"
huffman@47209
   890
  where [code del]: "pred_numeral k = numeral k - 1"
huffman@47209
   891
huffman@47209
   892
lemma numeral_eq_Suc: "numeral k = Suc (pred_numeral k)"
huffman@47209
   893
  unfolding pred_numeral_def by simp
huffman@47209
   894
huffman@47220
   895
lemma eval_nat_numeral:
huffman@47108
   896
  "numeral One = Suc 0"
huffman@47108
   897
  "numeral (Bit0 n) = Suc (numeral (BitM n))"
huffman@47108
   898
  "numeral (Bit1 n) = Suc (numeral (Bit0 n))"
huffman@47108
   899
  by (simp_all add: numeral.simps BitM_plus_one)
huffman@47108
   900
huffman@47209
   901
lemma pred_numeral_simps [simp]:
huffman@47300
   902
  "pred_numeral One = 0"
huffman@47300
   903
  "pred_numeral (Bit0 k) = numeral (BitM k)"
huffman@47300
   904
  "pred_numeral (Bit1 k) = numeral (Bit0 k)"
huffman@47220
   905
  unfolding pred_numeral_def eval_nat_numeral
huffman@47209
   906
  by (simp_all only: diff_Suc_Suc diff_0)
huffman@47209
   907
huffman@47192
   908
lemma numeral_2_eq_2: "2 = Suc (Suc 0)"
huffman@47220
   909
  by (simp add: eval_nat_numeral)
huffman@47192
   910
huffman@47192
   911
lemma numeral_3_eq_3: "3 = Suc (Suc (Suc 0))"
huffman@47220
   912
  by (simp add: eval_nat_numeral)
huffman@47192
   913
huffman@47207
   914
lemma numeral_1_eq_Suc_0: "Numeral1 = Suc 0"
huffman@47207
   915
  by (simp only: numeral_One One_nat_def)
huffman@47207
   916
huffman@47207
   917
lemma Suc_nat_number_of_add:
huffman@47300
   918
  "Suc (numeral v + n) = numeral (v + One) + n"
huffman@47207
   919
  by simp
huffman@47207
   920
huffman@47207
   921
(*Maps #n to n for n = 1, 2*)
huffman@47207
   922
lemmas numerals = numeral_One [where 'a=nat] numeral_2_eq_2
huffman@47207
   923
huffman@47209
   924
text {* Comparisons involving @{term Suc}. *}
huffman@47209
   925
huffman@47209
   926
lemma eq_numeral_Suc [simp]: "numeral k = Suc n \<longleftrightarrow> pred_numeral k = n"
huffman@47209
   927
  by (simp add: numeral_eq_Suc)
huffman@47209
   928
huffman@47209
   929
lemma Suc_eq_numeral [simp]: "Suc n = numeral k \<longleftrightarrow> n = pred_numeral k"
huffman@47209
   930
  by (simp add: numeral_eq_Suc)
huffman@47209
   931
huffman@47209
   932
lemma less_numeral_Suc [simp]: "numeral k < Suc n \<longleftrightarrow> pred_numeral k < n"
huffman@47209
   933
  by (simp add: numeral_eq_Suc)
huffman@47209
   934
huffman@47209
   935
lemma less_Suc_numeral [simp]: "Suc n < numeral k \<longleftrightarrow> n < pred_numeral k"
huffman@47209
   936
  by (simp add: numeral_eq_Suc)
huffman@47209
   937
huffman@47209
   938
lemma le_numeral_Suc [simp]: "numeral k \<le> Suc n \<longleftrightarrow> pred_numeral k \<le> n"
huffman@47209
   939
  by (simp add: numeral_eq_Suc)
huffman@47209
   940
huffman@47209
   941
lemma le_Suc_numeral [simp]: "Suc n \<le> numeral k \<longleftrightarrow> n \<le> pred_numeral k"
huffman@47209
   942
  by (simp add: numeral_eq_Suc)
huffman@47209
   943
huffman@47218
   944
lemma diff_Suc_numeral [simp]: "Suc n - numeral k = n - pred_numeral k"
huffman@47218
   945
  by (simp add: numeral_eq_Suc)
huffman@47218
   946
huffman@47218
   947
lemma diff_numeral_Suc [simp]: "numeral k - Suc n = pred_numeral k - n"
huffman@47218
   948
  by (simp add: numeral_eq_Suc)
huffman@47218
   949
huffman@47209
   950
lemma max_Suc_numeral [simp]:
huffman@47209
   951
  "max (Suc n) (numeral k) = Suc (max n (pred_numeral k))"
huffman@47209
   952
  by (simp add: numeral_eq_Suc)
huffman@47209
   953
huffman@47209
   954
lemma max_numeral_Suc [simp]:
huffman@47209
   955
  "max (numeral k) (Suc n) = Suc (max (pred_numeral k) n)"
huffman@47209
   956
  by (simp add: numeral_eq_Suc)
huffman@47209
   957
huffman@47209
   958
lemma min_Suc_numeral [simp]:
huffman@47209
   959
  "min (Suc n) (numeral k) = Suc (min n (pred_numeral k))"
huffman@47209
   960
  by (simp add: numeral_eq_Suc)
huffman@47209
   961
huffman@47209
   962
lemma min_numeral_Suc [simp]:
huffman@47209
   963
  "min (numeral k) (Suc n) = Suc (min (pred_numeral k) n)"
huffman@47209
   964
  by (simp add: numeral_eq_Suc)
huffman@47209
   965
huffman@47216
   966
text {* For @{term nat_case} and @{term nat_rec}. *}
huffman@47216
   967
huffman@47216
   968
lemma nat_case_numeral [simp]:
huffman@47216
   969
  "nat_case a f (numeral v) = (let pv = pred_numeral v in f pv)"
huffman@47216
   970
  by (simp add: numeral_eq_Suc)
huffman@47216
   971
huffman@47216
   972
lemma nat_case_add_eq_if [simp]:
huffman@47216
   973
  "nat_case a f ((numeral v) + n) = (let pv = pred_numeral v in f (pv + n))"
huffman@47216
   974
  by (simp add: numeral_eq_Suc)
huffman@47216
   975
huffman@47216
   976
lemma nat_rec_numeral [simp]:
huffman@47216
   977
  "nat_rec a f (numeral v) =
huffman@47216
   978
    (let pv = pred_numeral v in f pv (nat_rec a f pv))"
huffman@47216
   979
  by (simp add: numeral_eq_Suc Let_def)
huffman@47216
   980
huffman@47216
   981
lemma nat_rec_add_eq_if [simp]:
huffman@47216
   982
  "nat_rec a f (numeral v + n) =
huffman@47216
   983
    (let pv = pred_numeral v in f (pv + n) (nat_rec a f (pv + n)))"
huffman@47216
   984
  by (simp add: numeral_eq_Suc Let_def)
huffman@47216
   985
huffman@47255
   986
text {* Case analysis on @{term "n < 2"} *}
huffman@47255
   987
huffman@47255
   988
lemma less_2_cases: "n < 2 \<Longrightarrow> n = 0 \<or> n = Suc 0"
huffman@47255
   989
  by (auto simp add: numeral_2_eq_2)
huffman@47255
   990
huffman@47255
   991
text {* Removal of Small Numerals: 0, 1 and (in additive positions) 2 *}
huffman@47255
   992
text {* bh: Are these rules really a good idea? *}
huffman@47255
   993
huffman@47255
   994
lemma add_2_eq_Suc [simp]: "2 + n = Suc (Suc n)"
huffman@47255
   995
  by simp
huffman@47255
   996
huffman@47255
   997
lemma add_2_eq_Suc' [simp]: "n + 2 = Suc (Suc n)"
huffman@47255
   998
  by simp
huffman@47255
   999
huffman@47255
  1000
text {* Can be used to eliminate long strings of Sucs, but not by default. *}
huffman@47255
  1001
huffman@47255
  1002
lemma Suc3_eq_add_3: "Suc (Suc (Suc n)) = 3 + n"
huffman@47255
  1003
  by simp
huffman@47255
  1004
huffman@47255
  1005
lemmas nat_1_add_1 = one_add_one [where 'a=nat] (* legacy *)
huffman@47255
  1006
huffman@47108
  1007
huffman@47108
  1008
subsection {* Numeral equations as default simplification rules *}
huffman@47108
  1009
huffman@47108
  1010
declare (in numeral) numeral_One [simp]
huffman@47108
  1011
declare (in numeral) numeral_plus_numeral [simp]
huffman@47108
  1012
declare (in numeral) add_numeral_special [simp]
huffman@47108
  1013
declare (in neg_numeral) add_neg_numeral_simps [simp]
huffman@47108
  1014
declare (in neg_numeral) add_neg_numeral_special [simp]
huffman@47108
  1015
declare (in neg_numeral) diff_numeral_simps [simp]
huffman@47108
  1016
declare (in neg_numeral) diff_numeral_special [simp]
huffman@47108
  1017
declare (in semiring_numeral) numeral_times_numeral [simp]
huffman@47108
  1018
declare (in ring_1) mult_neg_numeral_simps [simp]
huffman@47108
  1019
huffman@47108
  1020
subsection {* Setting up simprocs *}
huffman@47108
  1021
huffman@47108
  1022
lemma mult_numeral_1: "Numeral1 * a = (a::'a::semiring_numeral)"
huffman@47108
  1023
  by simp
huffman@47108
  1024
huffman@47108
  1025
lemma mult_numeral_1_right: "a * Numeral1 = (a::'a::semiring_numeral)"
huffman@47108
  1026
  by simp
huffman@47108
  1027
huffman@47108
  1028
lemma divide_numeral_1: "a / Numeral1 = (a::'a::field)"
huffman@47108
  1029
  by simp
huffman@47108
  1030
huffman@47108
  1031
lemma inverse_numeral_1:
huffman@47108
  1032
  "inverse Numeral1 = (Numeral1::'a::division_ring)"
huffman@47108
  1033
  by simp
huffman@47108
  1034
huffman@47211
  1035
text{*Theorem lists for the cancellation simprocs. The use of a binary
huffman@47108
  1036
numeral for 1 reduces the number of special cases.*}
huffman@47108
  1037
huffman@47108
  1038
lemmas mult_1s =
huffman@47108
  1039
  mult_numeral_1 mult_numeral_1_right 
huffman@47108
  1040
  mult_minus1 mult_minus1_right
huffman@47108
  1041
huffman@47226
  1042
setup {*
huffman@47226
  1043
  Reorient_Proc.add
huffman@47226
  1044
    (fn Const (@{const_name numeral}, _) $ _ => true
huffman@47226
  1045
    | Const (@{const_name neg_numeral}, _) $ _ => true
huffman@47226
  1046
    | _ => false)
huffman@47226
  1047
*}
huffman@47226
  1048
huffman@47226
  1049
simproc_setup reorient_numeral
huffman@47226
  1050
  ("numeral w = x" | "neg_numeral w = y") = Reorient_Proc.proc
huffman@47226
  1051
huffman@47108
  1052
huffman@47108
  1053
subsubsection {* Simplification of arithmetic operations on integer constants. *}
huffman@47108
  1054
huffman@47108
  1055
lemmas arith_special = (* already declared simp above *)
huffman@47108
  1056
  add_numeral_special add_neg_numeral_special
huffman@47108
  1057
  diff_numeral_special minus_one
huffman@47108
  1058
huffman@47108
  1059
(* rules already in simpset *)
huffman@47108
  1060
lemmas arith_extra_simps =
huffman@47108
  1061
  numeral_plus_numeral add_neg_numeral_simps add_0_left add_0_right
huffman@47108
  1062
  minus_numeral minus_neg_numeral minus_zero minus_one
huffman@47108
  1063
  diff_numeral_simps diff_0 diff_0_right
huffman@47108
  1064
  numeral_times_numeral mult_neg_numeral_simps
huffman@47108
  1065
  mult_zero_left mult_zero_right
huffman@47108
  1066
  abs_numeral abs_neg_numeral
huffman@47108
  1067
huffman@47108
  1068
text {*
huffman@47108
  1069
  For making a minimal simpset, one must include these default simprules.
huffman@47108
  1070
  Also include @{text simp_thms}.
huffman@47108
  1071
*}
huffman@47108
  1072
huffman@47108
  1073
lemmas arith_simps =
huffman@47108
  1074
  add_num_simps mult_num_simps sub_num_simps
huffman@47108
  1075
  BitM.simps dbl_simps dbl_inc_simps dbl_dec_simps
huffman@47108
  1076
  abs_zero abs_one arith_extra_simps
huffman@47108
  1077
huffman@47108
  1078
text {* Simplification of relational operations *}
huffman@47108
  1079
huffman@47108
  1080
lemmas eq_numeral_extra =
huffman@47108
  1081
  zero_neq_one one_neq_zero
huffman@47108
  1082
huffman@47108
  1083
lemmas rel_simps =
huffman@47108
  1084
  le_num_simps less_num_simps eq_num_simps
huffman@47108
  1085
  le_numeral_simps le_neg_numeral_simps le_numeral_extra
huffman@47108
  1086
  less_numeral_simps less_neg_numeral_simps less_numeral_extra
huffman@47108
  1087
  eq_numeral_simps eq_neg_numeral_simps eq_numeral_extra
huffman@47108
  1088
huffman@47108
  1089
huffman@47108
  1090
subsubsection {* Simplification of arithmetic when nested to the right. *}
huffman@47108
  1091
huffman@47108
  1092
lemma add_numeral_left [simp]:
huffman@47108
  1093
  "numeral v + (numeral w + z) = (numeral(v + w) + z)"
huffman@47108
  1094
  by (simp_all add: add_assoc [symmetric])
huffman@47108
  1095
huffman@47108
  1096
lemma add_neg_numeral_left [simp]:
huffman@47108
  1097
  "numeral v + (neg_numeral w + y) = (sub v w + y)"
huffman@47108
  1098
  "neg_numeral v + (numeral w + y) = (sub w v + y)"
huffman@47108
  1099
  "neg_numeral v + (neg_numeral w + y) = (neg_numeral(v + w) + y)"
huffman@47108
  1100
  by (simp_all add: add_assoc [symmetric])
huffman@47108
  1101
huffman@47108
  1102
lemma mult_numeral_left [simp]:
huffman@47108
  1103
  "numeral v * (numeral w * z) = (numeral(v * w) * z :: 'a::semiring_numeral)"
huffman@47108
  1104
  "neg_numeral v * (numeral w * y) = (neg_numeral(v * w) * y :: 'b::ring_1)"
huffman@47108
  1105
  "numeral v * (neg_numeral w * y) = (neg_numeral(v * w) * y :: 'b::ring_1)"
huffman@47108
  1106
  "neg_numeral v * (neg_numeral w * y) = (numeral(v * w) * y :: 'b::ring_1)"
huffman@47108
  1107
  by (simp_all add: mult_assoc [symmetric])
huffman@47108
  1108
huffman@47108
  1109
hide_const (open) One Bit0 Bit1 BitM inc pow sqr sub dbl dbl_inc dbl_dec
huffman@47108
  1110
haftmann@51143
  1111
huffman@47108
  1112
subsection {* code module namespace *}
huffman@47108
  1113
huffman@47108
  1114
code_modulename SML
huffman@47126
  1115
  Num Arith
huffman@47108
  1116
huffman@47108
  1117
code_modulename OCaml
huffman@47126
  1118
  Num Arith
huffman@47108
  1119
huffman@47108
  1120
code_modulename Haskell
huffman@47126
  1121
  Num Arith
huffman@47108
  1122
huffman@47108
  1123
end
haftmann@50817
  1124
haftmann@51143
  1125