--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Library/Executable_Real.thy Tue May 15 18:28:02 2007 +0200
@@ -0,0 +1,484 @@
+(* Title: HOL/Library/Executable_Real.thy
+ ID: $Id$
+ Author: Amine Chaieb, TU Muenchen
+*)
+
+header {* Implementation of rational real numbers as pairs of integers *}
+
+theory Executable_Real
+imports GCD "~~/src/HOL/Real/Real"
+begin
+
+subsection {* Implementation of operations on pair of integers *}
+
+types Num = "int * int"
+syntax "_Num0" :: "Num" ("0\<^sub>N")
+translations "0\<^sub>N" \<rightleftharpoons> "(0,0)"
+syntax "_Numi" :: "int \<Rightarrow> Num" ("_\<^sub>N")
+translations "i\<^sub>N" \<rightleftharpoons> "(i,1)::Num"
+
+constdefs isnormNum :: "Num \<Rightarrow> bool"
+ "isnormNum \<equiv> \<lambda>(a,b). (if a = 0 then b = 0 else b > 0 \<and> igcd a b = 1)"
+
+constdefs normNum :: "Num \<Rightarrow> Num"
+ "normNum \<equiv> \<lambda>(a,b). (if a=0 \<or> b = 0 then (0,0) else
+ (let g = igcd a b
+ in if b > 0 then (a div g, b div g) else (- (a div g), - (b div g))))"
+lemma normNum_isnormNum[simp]: "isnormNum (normNum x)"
+proof-
+ have " \<exists> a b. x = (a,b)" by auto
+ then obtain a b where x[simp]: "x = (a,b)" by blast
+ {assume "a=0 \<or> b = 0" hence ?thesis by (simp add: normNum_def isnormNum_def)}
+ moreover
+ {assume anz: "a \<noteq> 0" and bnz: "b \<noteq> 0"
+ let ?g = "igcd a b"
+ let ?a' = "a div ?g"
+ let ?b' = "b div ?g"
+ let ?g' = "igcd ?a' ?b'"
+ from anz bnz have "?g \<noteq> 0" by simp with igcd_pos[of a b]
+ have gpos: "?g > 0" by arith
+ have gdvd: "?g dvd a" "?g dvd b" by (simp_all add: igcd_dvd1 igcd_dvd2)
+ from zdvd_mult_div_cancel[OF gdvd(1)] zdvd_mult_div_cancel[OF gdvd(2)]
+ anz bnz
+ have nz':"?a' \<noteq> 0" "?b' \<noteq> 0"
+ by - (rule notI,simp add:igcd_def)+
+ from anz bnz have stupid: "a \<noteq> 0 \<or> b \<noteq> 0" by blast
+ from div_igcd_relprime[OF stupid] have gp1: "?g' = 1" .
+ from bnz have "b < 0 \<or> b > 0" by arith
+ moreover
+ {assume b: "b > 0"
+ from pos_imp_zdiv_nonneg_iff[OF gpos] b
+ have "?b' \<ge> 0" by simp
+ with nz' have b': "?b' > 0" by simp
+ from b b' anz bnz nz' gp1 have ?thesis
+ by (simp add: isnormNum_def normNum_def Let_def split_def fst_conv snd_conv)}
+ moreover {assume b: "b < 0"
+ {assume b': "?b' \<ge> 0"
+ from gpos have th: "?g \<ge> 0" by arith
+ from mult_nonneg_nonneg[OF th b'] zdvd_mult_div_cancel[OF gdvd(2)]
+ have False using b by simp }
+ hence b': "?b' < 0" by arith
+ from anz bnz nz' b b' gp1 have ?thesis
+ by (simp add: isnormNum_def normNum_def Let_def split_def fst_conv snd_conv)}
+ ultimately have ?thesis by blast
+ }
+ ultimately show ?thesis by blast
+qed
+ (* Arithmetic over Num *)
+constdefs Nadd :: "Num \<Rightarrow> Num \<Rightarrow> Num" (infixl "+\<^sub>N" 60)
+ "Nadd \<equiv> \<lambda>(a,b) (a',b'). if a = 0 \<or> b = 0 then normNum(a',b')
+ else if a'=0 \<or> b' = 0 then normNum(a,b)
+ else normNum(a*b' + b*a', b*b')"
+constdefs Nmul :: "Num \<Rightarrow> Num \<Rightarrow> Num" (infixl "*\<^sub>N" 60)
+ "Nmul \<equiv> \<lambda>(a,b) (a',b'). let g = igcd (a*a') (b*b')
+ in (a*a' div g, b*b' div g)"
+constdefs Nneg :: "Num \<Rightarrow> Num" ("~\<^sub>N")
+ "Nneg \<equiv> \<lambda>(a,b). (-a,b)"
+constdefs Nsub :: "Num \<Rightarrow> Num \<Rightarrow> Num" (infixl "-\<^sub>N" 60)
+ "Nsub \<equiv> \<lambda>a b. a +\<^sub>N ~\<^sub>N b"
+constdefs Ninv :: "Num \<Rightarrow> Num"
+"Ninv \<equiv> \<lambda>(a,b). if a < 0 then (-b, \<bar>a\<bar>) else (b,a)"
+constdefs Ndiv :: "Num \<Rightarrow> Num \<Rightarrow> Num" (infixl "\<div>\<^sub>N" 60)
+ "Ndiv \<equiv> \<lambda>a b. a *\<^sub>N Ninv b"
+
+lemma Nneg_normN[simp]: "isnormNum x \<Longrightarrow> isnormNum (~\<^sub>N x)"
+ by(simp add: isnormNum_def Nneg_def split_def)
+lemma Nadd_normN[simp]: "isnormNum (x +\<^sub>N y)"
+ by (simp add: Nadd_def split_def)
+lemma Nsub_normN[simp]: "\<lbrakk> isnormNum y\<rbrakk> \<Longrightarrow> isnormNum (x -\<^sub>N y)"
+ by (simp add: Nsub_def split_def)
+lemma Nmul_normN[simp]: assumes xn:"isnormNum x" and yn: "isnormNum y"
+ shows "isnormNum (x *\<^sub>N y)"
+proof-
+ have "\<exists>a b. x = (a,b)" and "\<exists> a' b'. y = (a',b')" by auto
+ then obtain a b a' b' where ab: "x = (a,b)" and ab': "y = (a',b')" by blast
+ {assume "a = 0"
+ hence ?thesis using xn ab ab'
+ by (simp add: igcd_def isnormNum_def Let_def Nmul_def split_def)}
+ moreover
+ {assume "a' = 0"
+ hence ?thesis using yn ab ab'
+ by (simp add: igcd_def isnormNum_def Let_def Nmul_def split_def)}
+ moreover
+ {assume a: "a \<noteq>0" and a': "a'\<noteq>0"
+ hence bp: "b > 0" "b' > 0" using xn yn ab ab' by (simp_all add: isnormNum_def)
+ from mult_pos_pos[OF bp] have "x *\<^sub>N y = normNum (a*a', b*b')"
+ using ab ab' a a' bp by (simp add: Nmul_def Let_def split_def normNum_def)
+ hence ?thesis by simp}
+ ultimately show ?thesis by blast
+qed
+
+lemma Ninv_normN[simp]: "isnormNum x \<Longrightarrow> isnormNum (Ninv x)"
+by (simp add: Ninv_def isnormNum_def split_def)
+(cases "fst x = 0",auto simp add: igcd_commute)
+
+lemma isnormNum_int[simp]:
+ "isnormNum 0\<^sub>N" "isnormNum (1::int)\<^sub>N" "i \<noteq> 0 \<Longrightarrow> isnormNum i\<^sub>N"
+ by (simp_all add: isnormNum_def igcd_def)
+
+ (* Relations over Num *)
+constdefs Nlt0:: "Num \<Rightarrow> bool" ("0>\<^sub>N")
+ "Nlt0 \<equiv> \<lambda>(a,b). a < 0"
+constdefs Nle0:: "Num \<Rightarrow> bool" ("0\<ge>\<^sub>N")
+ "Nle0 \<equiv> \<lambda>(a,b). a \<le> 0"
+constdefs Ngt0:: "Num \<Rightarrow> bool" ("0<\<^sub>N")
+ "Ngt0 \<equiv> \<lambda>(a,b). a > 0"
+constdefs Nge0:: "Num \<Rightarrow> bool" ("0\<le>\<^sub>N")
+ "Nge0 \<equiv> \<lambda>(a,b). a \<ge> 0"
+constdefs Nlt :: "Num \<Rightarrow> Num \<Rightarrow> bool" (infix "<\<^sub>N" 55)
+ "Nlt \<equiv> \<lambda>a b. 0>\<^sub>N (a -\<^sub>N b)"
+constdefs Nle :: "Num \<Rightarrow> Num \<Rightarrow> bool" (infix "\<le>\<^sub>N" 55)
+ "Nle \<equiv> \<lambda>a b. 0\<ge>\<^sub>N (a -\<^sub>N b)"
+
+
+subsection {* Interpretation of the normalized rats in \<real> *}
+
+definition
+ INum:: "Num \<Rightarrow> real"
+where
+ INum_def: "INum \<equiv> \<lambda>(a,b). real a / real b"
+
+code_datatype INum
+instance real :: eq ..
+
+definition
+ real_int :: "int \<Rightarrow> real"
+where
+ "real_int = real"
+lemmas [code unfold] = real_int_def [symmetric]
+
+lemma [code unfold]:
+ "real = real_int o int"
+ by (auto simp add: real_int_def expand_fun_eq)
+
+lemma INum_int [simp]: "INum i\<^sub>N = real i" "INum 0\<^sub>N = 0"
+ by (simp_all add: INum_def)
+lemmas [code, code unfold] = INum_int [unfolded real_int_def [symmetric], symmetric]
+
+lemma [code, code unfold]: "1 = INum 1\<^sub>N" by simp
+
+lemma isnormNum_unique[simp]:
+ assumes na: "isnormNum x" and nb: "isnormNum y"
+ shows "(INum x = INum y) = (x = y)" (is "?lhs = ?rhs")
+proof
+ have "\<exists> a b a' b'. x = (a,b) \<and> y = (a',b')" by auto
+ then obtain a b a' b' where xy[simp]: "x = (a,b)" "y=(a',b')" by blast
+ assume H: ?lhs
+ {assume "a = 0 \<or> b = 0 \<or> a' = 0 \<or> b' = 0" hence ?rhs
+ using na nb H
+ by (simp add: INum_def split_def isnormNum_def)
+ (cases "a = 0", simp_all,cases "b = 0", simp_all,
+ cases "a' = 0", simp_all,cases "a' = 0", simp_all)}
+ moreover
+ { assume az: "a \<noteq> 0" and bz: "b \<noteq> 0" and a'z: "a'\<noteq>0" and b'z: "b'\<noteq>0"
+ from az bz a'z b'z na nb have pos: "b > 0" "b' > 0" by (simp_all add: isnormNum_def)
+ from prems have eq:"a * b' = a'*b"
+ by (simp add: INum_def eq_divide_eq divide_eq_eq real_of_int_mult[symmetric] del: real_of_int_mult)
+ from prems have gcd1: "igcd a b = 1" "igcd b a = 1" "igcd a' b' = 1" "igcd b' a' = 1"
+ by (simp_all add: isnormNum_def add: igcd_commute)
+ from eq have raw_dvd: "a dvd a'*b" "b dvd b'*a" "a' dvd a*b'" "b' dvd b*a'"
+ apply(unfold dvd_def)
+ apply (rule_tac x="b'" in exI, simp add: mult_ac)
+ apply (rule_tac x="a'" in exI, simp add: mult_ac)
+ apply (rule_tac x="b" in exI, simp add: mult_ac)
+ apply (rule_tac x="a" in exI, simp add: mult_ac)
+ done
+ from zdvd_dvd_eq[OF bz zrelprime_dvd_mult[OF gcd1(2) raw_dvd(2)]
+ zrelprime_dvd_mult[OF gcd1(4) raw_dvd(4)]]
+ have eq1: "b = b'" using pos by simp_all
+ with eq have "a = a'" using pos by simp
+ with eq1 have ?rhs by simp}
+ ultimately show ?rhs by blast
+next
+ assume ?rhs thus ?lhs by simp
+qed
+
+
+lemma isnormNum0[simp]: "isnormNum x \<Longrightarrow> (INum x = 0) = (x = 0\<^sub>N)"
+ unfolding INum_int(2)[symmetric]
+ by (rule isnormNum_unique, simp_all)
+
+lemma normNum[simp]: "INum (normNum x) = INum x"
+proof-
+ have "\<exists> a b. x = (a,b)" by auto
+ then obtain a b where x[simp]: "x = (a,b)" by blast
+ {assume "a=0 \<or> b = 0" hence ?thesis
+ by (simp add: INum_def normNum_def split_def Let_def)}
+ moreover
+ {assume a: "a\<noteq>0" and b: "b\<noteq>0"
+ let ?g = "igcd a b"
+ from a b have g: "?g \<noteq> 0"by simp
+ from real_of_int_div[OF g]
+ have ?thesis by (simp add: INum_def normNum_def split_def Let_def)}
+ ultimately show ?thesis by blast
+qed
+
+lemma INum_normNum_iff [code]: "INum x = INum y \<longleftrightarrow> normNum x = normNum y" (is "?lhs = ?rhs")
+proof -
+ have "normNum x = normNum y \<longleftrightarrow> INum (normNum x) = INum (normNum y)"
+ by (simp del: normNum)
+ also have "\<dots> = ?lhs" by simp
+ finally show ?thesis by simp
+qed
+
+lemma Nadd[simp]: "INum (x +\<^sub>N y) = INum x + INum y"
+proof-
+ have " \<exists> a b. x = (a,b)" " \<exists> a' b'. y = (a',b')" by auto
+ then obtain a b a' b' where x[simp]: "x = (a,b)"
+ and y[simp]: "y = (a',b')" by blast
+ {assume "a=0 \<or> a'= 0 \<or> b =0 \<or> b' = 0" hence ?thesis
+ apply (cases "a=0",simp_all add: Nadd_def)
+ apply (cases "b= 0",simp_all add: INum_def)
+ apply (cases "a'= 0",simp_all)
+ apply (cases "b'= 0",simp_all)
+ done }
+ moreover
+ {assume aa':"a \<noteq> 0" "a'\<noteq> 0" and bb': "b \<noteq> 0" "b' \<noteq> 0"
+ {assume z: "a * b' + b * a' = 0"
+ hence "real (a*b' + b*a') / (real b* real b') = 0" by simp
+ hence "real b' * real a / (real b * real b') + real b * real a' / (real b * real b') = 0" by (simp add:add_divide_distrib)
+ hence th: "real a / real b + real a' / real b' = 0" using bb' aa' by simp
+ from z aa' bb' have ?thesis
+ by (simp add: th Nadd_def normNum_def INum_def split_def)}
+ moreover {assume z: "a * b' + b * a' \<noteq> 0"
+ let ?g = "igcd (a * b' + b * a') (b*b')"
+ have gz: "?g \<noteq> 0" using z by simp
+ have ?thesis using aa' bb' z gz
+ real_of_int_div[OF gz igcd_dvd1[where i="a * b' + b * a'" and j="b*b'"]]
+ real_of_int_div[OF gz igcd_dvd2[where i="a * b' + b * a'" and j="b*b'"]]
+ by (simp add: x y Nadd_def INum_def normNum_def Let_def add_divide_distrib)}
+ ultimately have ?thesis using aa' bb'
+ by (simp add: Nadd_def INum_def normNum_def x y Let_def) }
+ ultimately show ?thesis by blast
+qed
+lemmas [code] = Nadd [symmetric]
+
+lemma Nmul[simp]: "INum (x *\<^sub>N y) = INum x * INum y"
+proof-
+ have " \<exists> a b. x = (a,b)" " \<exists> a' b'. y = (a',b')" by auto
+ then obtain a b a' b' where x: "x = (a,b)" and y: "y = (a',b')" by blast
+ {assume "a=0 \<or> a'= 0 \<or> b = 0 \<or> b' = 0" hence ?thesis
+ apply (cases "a=0",simp_all add: x y Nmul_def INum_def Let_def)
+ apply (cases "b=0",simp_all)
+ apply (cases "a'=0",simp_all)
+ done }
+ moreover
+ {assume z: "a \<noteq> 0" "a' \<noteq> 0" "b \<noteq> 0" "b' \<noteq> 0"
+ let ?g="igcd (a*a') (b*b')"
+ have gz: "?g \<noteq> 0" using z by simp
+ from z real_of_int_div[OF gz igcd_dvd1[where i="a*a'" and j="b*b'"]]
+ real_of_int_div[OF gz igcd_dvd2[where i="a*a'" and j="b*b'"]]
+ have ?thesis by (simp add: Nmul_def x y Let_def INum_def)}
+ ultimately show ?thesis by blast
+qed
+lemmas [code] = Nmul [symmetric]
+
+lemma Nneg[simp]: "INum (~\<^sub>N x) = - INum x"
+ by (simp add: Nneg_def split_def INum_def)
+lemmas [code] = Nneg [symmetric]
+
+lemma Nsub[simp]: shows "INum (x -\<^sub>N y) = INum x - INum y"
+ by (simp add: Nsub_def split_def)
+lemmas [code] = Nsub [symmetric]
+
+lemma Ninv[simp]: "INum (Ninv x) = 1 / (INum x)"
+ by (simp add: Ninv_def INum_def split_def)
+lemmas [code] = Ninv [symmetric]
+
+lemma Ndiv[simp]: "INum (x \<div>\<^sub>N y) = INum x / INum y" by (simp add: Ndiv_def)
+lemmas [code] = Ndiv [symmetric]
+
+lemma Nlt0_iff[simp]: assumes nx: "isnormNum x" shows "(INum x < 0) = 0>\<^sub>N x "
+proof-
+ have " \<exists> a b. x = (a,b)" by simp
+ then obtain a b where x[simp]:"x = (a,b)" by blast
+ {assume "a = 0" hence ?thesis by (simp add: Nlt0_def INum_def) }
+ moreover
+ {assume a: "a\<noteq>0" hence b: "real b > 0" using nx by (simp add: isnormNum_def)
+ from pos_divide_less_eq[OF b, where b="real a" and a="0"]
+ have ?thesis by (simp add: Nlt0_def INum_def)}
+ ultimately show ?thesis by blast
+qed
+
+lemma Nle0_iff[simp]:assumes nx: "isnormNum x" shows "(INum x \<le> 0) = 0\<ge>\<^sub>N x"
+proof-
+ have " \<exists> a b. x = (a,b)" by simp
+ then obtain a b where x[simp]:"x = (a,b)" by blast
+ {assume "a = 0" hence ?thesis by (simp add: Nle0_def INum_def) }
+ moreover
+ {assume a: "a\<noteq>0" hence b: "real b > 0" using nx by (simp add: isnormNum_def)
+ from pos_divide_le_eq[OF b, where b="real a" and a="0"]
+ have ?thesis by (simp add: Nle0_def INum_def)}
+ ultimately show ?thesis by blast
+qed
+
+lemma Ngt0_iff[simp]:assumes nx: "isnormNum x" shows "(INum x > 0) = 0<\<^sub>N x"
+proof-
+ have " \<exists> a b. x = (a,b)" by simp
+ then obtain a b where x[simp]:"x = (a,b)" by blast
+ {assume "a = 0" hence ?thesis by (simp add: Ngt0_def INum_def) }
+ moreover
+ {assume a: "a\<noteq>0" hence b: "real b > 0" using nx by (simp add: isnormNum_def)
+ from pos_less_divide_eq[OF b, where b="real a" and a="0"]
+ have ?thesis by (simp add: Ngt0_def INum_def)}
+ ultimately show ?thesis by blast
+qed
+lemma Nge0_iff[simp]:assumes nx: "isnormNum x" shows "(INum x \<ge> 0) = 0\<le>\<^sub>N x"
+proof-
+ have " \<exists> a b. x = (a,b)" by simp
+ then obtain a b where x[simp]:"x = (a,b)" by blast
+ {assume "a = 0" hence ?thesis by (simp add: Nge0_def INum_def) }
+ moreover
+ {assume a: "a\<noteq>0" hence b: "real b > 0" using nx by (simp add: isnormNum_def)
+ from pos_le_divide_eq[OF b, where b="real a" and a="0"]
+ have ?thesis by (simp add: Nge0_def INum_def)}
+ ultimately show ?thesis by blast
+qed
+
+lemma Nlt_iff[simp]: assumes nx: "isnormNum x" and ny: "isnormNum y"
+ shows "(INum x < INum y) = (x <\<^sub>N y)"
+proof-
+ have "(INum x < INum y) = (INum (x -\<^sub>N y) < 0)" using nx ny by simp
+ also have "\<dots> = (0>\<^sub>N (x -\<^sub>N y))" using Nlt0_iff[OF Nsub_normN[OF ny]] by simp
+ finally show ?thesis by (simp add: Nlt_def)
+qed
+
+lemma [code]: "INum x < INum y \<longleftrightarrow> normNum x <\<^sub>N normNum y"
+proof -
+ have "normNum x <\<^sub>N normNum y \<longleftrightarrow> INum (normNum x) < INum (normNum y)"
+ by (simp del: normNum)
+ also have "\<dots> = (INum x < INum y)" by simp
+ finally show ?thesis by simp
+qed
+
+lemma Nle_iff[simp]: assumes nx: "isnormNum x" and ny: "isnormNum y"
+ shows "(INum x \<le> INum y) = (x \<le>\<^sub>N y)"
+proof-
+ have "(INum x \<le> INum y) = (INum (x -\<^sub>N y) \<le> 0)" using nx ny by simp
+ also have "\<dots> = (0\<ge>\<^sub>N (x -\<^sub>N y))" using Nle0_iff[OF Nsub_normN[OF ny]] by simp
+ finally show ?thesis by (simp add: Nle_def)
+qed
+
+lemma [code]: "INum x \<le> INum y \<longleftrightarrow> normNum x \<le>\<^sub>N normNum y"
+proof -
+ have "normNum x \<le>\<^sub>N normNum y \<longleftrightarrow> INum (normNum x) \<le> INum (normNum y)"
+ by (simp del: normNum)
+ also have "\<dots> = (INum x \<le> INum y)" by simp
+ finally show ?thesis by simp
+qed
+
+lemma Nadd_commute: "x +\<^sub>N y = y +\<^sub>N x"
+proof-
+ have n: "isnormNum (x +\<^sub>N y)" "isnormNum (y +\<^sub>N x)" by simp_all
+ have "INum (x +\<^sub>N y) = INum (y +\<^sub>N x)" by simp
+ with isnormNum_unique[OF n] show ?thesis by simp
+qed
+
+lemma[simp]: "(0, b) +\<^sub>N y = normNum y" "(a, 0) +\<^sub>N y = normNum y"
+ "x +\<^sub>N (0, b) = normNum x" "x +\<^sub>N (a, 0) = normNum x"
+ apply (simp add: Nadd_def split_def, simp add: Nadd_def split_def)
+ apply (subst Nadd_commute,simp add: Nadd_def split_def)
+ apply (subst Nadd_commute,simp add: Nadd_def split_def)
+ done
+
+lemma normNum_nilpotent_aux[simp]: assumes nx: "isnormNum x"
+ shows "normNum x = x"
+proof-
+ let ?a = "normNum x"
+ have n: "isnormNum ?a" by simp
+ have th:"INum ?a = INum x" by simp
+ with isnormNum_unique[OF n nx]
+ show ?thesis by simp
+qed
+
+lemma normNum_nilpotent[simp]: "normNum (normNum x) = normNum x"
+ by simp
+lemma normNum0[simp]: "normNum (0,b) = 0\<^sub>N" "normNum (a,0) = 0\<^sub>N"
+ by (simp_all add: normNum_def)
+lemma normNum_Nadd: "normNum (x +\<^sub>N y) = x +\<^sub>N y" by simp
+lemma Nadd_normNum1[simp]: "normNum x +\<^sub>N y = x +\<^sub>N y"
+proof-
+ have n: "isnormNum (normNum x +\<^sub>N y)" "isnormNum (x +\<^sub>N y)" by simp_all
+ have "INum (normNum x +\<^sub>N y) = INum x + INum y" by simp
+ also have "\<dots> = INum (x +\<^sub>N y)" by simp
+ finally show ?thesis using isnormNum_unique[OF n] by simp
+qed
+lemma Nadd_normNum2[simp]: "x +\<^sub>N normNum y = x +\<^sub>N y"
+proof-
+ have n: "isnormNum (x +\<^sub>N normNum y)" "isnormNum (x +\<^sub>N y)" by simp_all
+ have "INum (x +\<^sub>N normNum y) = INum x + INum y" by simp
+ also have "\<dots> = INum (x +\<^sub>N y)" by simp
+ finally show ?thesis using isnormNum_unique[OF n] by simp
+qed
+
+lemma Nadd_assoc: "x +\<^sub>N y +\<^sub>N z = x +\<^sub>N (y +\<^sub>N z)"
+proof-
+ have n: "isnormNum (x +\<^sub>N y +\<^sub>N z)" "isnormNum (x +\<^sub>N (y +\<^sub>N z))" by simp_all
+ have "INum (x +\<^sub>N y +\<^sub>N z) = INum (x +\<^sub>N (y +\<^sub>N z))" by simp
+ with isnormNum_unique[OF n] show ?thesis by simp
+qed
+
+lemma Nmul_commute: "isnormNum x \<Longrightarrow> isnormNum y \<Longrightarrow> x *\<^sub>N y = y *\<^sub>N x"
+ by (simp add: Nmul_def split_def Let_def igcd_commute mult_commute)
+
+lemma Nmul_assoc: assumes nx: "isnormNum x" and ny:"isnormNum y" and nz:"isnormNum z"
+ shows "x *\<^sub>N y *\<^sub>N z = x *\<^sub>N (y *\<^sub>N z)"
+proof-
+ from nx ny nz have n: "isnormNum (x *\<^sub>N y *\<^sub>N z)" "isnormNum (x *\<^sub>N (y *\<^sub>N z))"
+ by simp_all
+ have "INum (x +\<^sub>N y +\<^sub>N z) = INum (x +\<^sub>N (y +\<^sub>N z))" by simp
+ with isnormNum_unique[OF n] show ?thesis by simp
+qed
+
+lemma Nsub0: assumes x: "isnormNum x" and y:"isnormNum y" shows "(x -\<^sub>N y = 0\<^sub>N) = (x = y)"
+proof-
+ from isnormNum_unique[OF Nsub_normN[OF y], where y="0\<^sub>N"]
+ have "(x -\<^sub>N y = 0\<^sub>N) = (INum (x -\<^sub>N y) = INum 0\<^sub>N)" by simp
+ also have "\<dots> = (INum x = INum y)" by simp
+ also have "\<dots> = (x = y)" using x y by simp
+ finally show ?thesis .
+qed
+lemma Nmul0[simp]: "c *\<^sub>N 0\<^sub>N = 0\<^sub>N" " 0\<^sub>N *\<^sub>N c = 0\<^sub>N"
+ by (simp_all add: Nmul_def Let_def split_def)
+
+lemma Nmul_eq0[simp]: assumes nx:"isnormNum x" and ny: "isnormNum y"
+ shows "(x*\<^sub>N y = 0\<^sub>N) = (x = 0\<^sub>N \<or> y = 0\<^sub>N)"
+proof-
+ have " \<exists> a b a' b'. x = (a,b) \<and> y= (a',b')" by auto
+ then obtain a b a' b' where xy[simp]: "x = (a,b)" "y = (a',b')" by blast
+ have n0: "isnormNum 0\<^sub>N" by simp
+ show ?thesis using nx ny
+ apply (simp only: isnormNum_unique[OF Nmul_normN[OF nx ny] n0, symmetric] Nmul)
+ apply (simp add: INum_def split_def isnormNum_def fst_conv snd_conv)
+ apply (cases "a=0",simp_all)
+ apply (cases "a'=0",simp_all)
+ done
+qed
+lemma Nneg_Nneg[simp]: "~\<^sub>N (~\<^sub>N c) = c"
+ by (simp add: Nneg_def split_def)
+
+lemma Nmul1[simp]:
+ "isnormNum c \<Longrightarrow> 1\<^sub>N *\<^sub>N c = c"
+ "isnormNum c \<Longrightarrow> c *\<^sub>N 1\<^sub>N = c"
+ apply (simp_all add: Nmul_def Let_def split_def isnormNum_def)
+ by (cases "fst c = 0", simp_all,cases c, simp_all)+
+
+lemma [code, code unfold]:
+ "number_of k = real_int (number_of k)"
+ by (simp add: real_int_def)
+
+types_code real ("{* int * int *}")
+attach (term_of) {*
+fun term_of_real (p, q) =
+ let
+ val rT = HOLogic.realT;
+in if q = 1
+ then HOLogic.mk_number rT p
+ else Const ("HOL.divide", rT --> rT --> rT) $
+ HOLogic.mk_number rT p $ HOLogic.mk_number rT q
+end;
+*}
+
+consts_code INum ("")
+
+end
\ No newline at end of file