src/HOL/NatBin.thy
changeset 30944 7ac037c75c26
parent 30902 5c8618f95d24
parent 30943 eb3dbbe971f6
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     1 (*  Title:      HOL/NatBin.thy
       
     2     Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
       
     3     Copyright   1999  University of Cambridge
       
     4 *)
       
     5 
       
     6 header {* Binary arithmetic for the natural numbers *}
       
     7 
       
     8 theory NatBin
       
     9 imports IntDiv
       
    10 uses ("Tools/nat_simprocs.ML")
       
    11 begin
       
    12 
       
    13 text {*
       
    14   Arithmetic for naturals is reduced to that for the non-negative integers.
       
    15 *}
       
    16 
       
    17 instantiation nat :: number
       
    18 begin
       
    19 
       
    20 definition
       
    21   nat_number_of_def [code inline, code del]: "number_of v = nat (number_of v)"
       
    22 
       
    23 instance ..
       
    24 
       
    25 end
       
    26 
       
    27 lemma [code post]:
       
    28   "nat (number_of v) = number_of v"
       
    29   unfolding nat_number_of_def ..
       
    30 
       
    31 abbreviation (xsymbols)
       
    32   power2 :: "'a::power => 'a"  ("(_\<twosuperior>)" [1000] 999) where
       
    33   "x\<twosuperior> == x^2"
       
    34 
       
    35 notation (latex output)
       
    36   power2  ("(_\<twosuperior>)" [1000] 999)
       
    37 
       
    38 notation (HTML output)
       
    39   power2  ("(_\<twosuperior>)" [1000] 999)
       
    40 
       
    41 
       
    42 subsection {* Predicate for negative binary numbers *}
       
    43 
       
    44 definition neg  :: "int \<Rightarrow> bool" where
       
    45   "neg Z \<longleftrightarrow> Z < 0"
       
    46 
       
    47 lemma not_neg_int [simp]: "~ neg (of_nat n)"
       
    48 by (simp add: neg_def)
       
    49 
       
    50 lemma neg_zminus_int [simp]: "neg (- (of_nat (Suc n)))"
       
    51 by (simp add: neg_def neg_less_0_iff_less del: of_nat_Suc)
       
    52 
       
    53 lemmas neg_eq_less_0 = neg_def
       
    54 
       
    55 lemma not_neg_eq_ge_0: "(~neg x) = (0 \<le> x)"
       
    56 by (simp add: neg_def linorder_not_less)
       
    57 
       
    58 text{*To simplify inequalities when Numeral1 can get simplified to 1*}
       
    59 
       
    60 lemma not_neg_0: "~ neg 0"
       
    61 by (simp add: One_int_def neg_def)
       
    62 
       
    63 lemma not_neg_1: "~ neg 1"
       
    64 by (simp add: neg_def linorder_not_less zero_le_one)
       
    65 
       
    66 lemma neg_nat: "neg z ==> nat z = 0"
       
    67 by (simp add: neg_def order_less_imp_le) 
       
    68 
       
    69 lemma not_neg_nat: "~ neg z ==> of_nat (nat z) = z"
       
    70 by (simp add: linorder_not_less neg_def)
       
    71 
       
    72 text {*
       
    73   If @{term Numeral0} is rewritten to 0 then this rule can't be applied:
       
    74   @{term Numeral0} IS @{term "number_of Pls"}
       
    75 *}
       
    76 
       
    77 lemma not_neg_number_of_Pls: "~ neg (number_of Int.Pls)"
       
    78   by (simp add: neg_def)
       
    79 
       
    80 lemma neg_number_of_Min: "neg (number_of Int.Min)"
       
    81   by (simp add: neg_def)
       
    82 
       
    83 lemma neg_number_of_Bit0:
       
    84   "neg (number_of (Int.Bit0 w)) = neg (number_of w)"
       
    85   by (simp add: neg_def)
       
    86 
       
    87 lemma neg_number_of_Bit1:
       
    88   "neg (number_of (Int.Bit1 w)) = neg (number_of w)"
       
    89   by (simp add: neg_def)
       
    90 
       
    91 lemmas neg_simps [simp] =
       
    92   not_neg_0 not_neg_1
       
    93   not_neg_number_of_Pls neg_number_of_Min
       
    94   neg_number_of_Bit0 neg_number_of_Bit1
       
    95 
       
    96 
       
    97 subsection{*Function @{term nat}: Coercion from Type @{typ int} to @{typ nat}*}
       
    98 
       
    99 declare nat_0 [simp] nat_1 [simp]
       
   100 
       
   101 lemma nat_number_of [simp]: "nat (number_of w) = number_of w"
       
   102 by (simp add: nat_number_of_def)
       
   103 
       
   104 lemma nat_numeral_0_eq_0 [simp]: "Numeral0 = (0::nat)"
       
   105 by (simp add: nat_number_of_def)
       
   106 
       
   107 lemma nat_numeral_1_eq_1 [simp]: "Numeral1 = (1::nat)"
       
   108 by (simp add: nat_1 nat_number_of_def)
       
   109 
       
   110 lemma numeral_1_eq_Suc_0: "Numeral1 = Suc 0"
       
   111 by (simp add: nat_numeral_1_eq_1)
       
   112 
       
   113 lemma numeral_2_eq_2: "2 = Suc (Suc 0)"
       
   114 apply (unfold nat_number_of_def)
       
   115 apply (rule nat_2)
       
   116 done
       
   117 
       
   118 
       
   119 subsection{*Function @{term int}: Coercion from Type @{typ nat} to @{typ int}*}
       
   120 
       
   121 lemma int_nat_number_of [simp]:
       
   122      "int (number_of v) =  
       
   123          (if neg (number_of v :: int) then 0  
       
   124           else (number_of v :: int))"
       
   125   unfolding nat_number_of_def number_of_is_id neg_def
       
   126   by simp
       
   127 
       
   128 
       
   129 subsubsection{*Successor *}
       
   130 
       
   131 lemma Suc_nat_eq_nat_zadd1: "(0::int) <= z ==> Suc (nat z) = nat (1 + z)"
       
   132 apply (rule sym)
       
   133 apply (simp add: nat_eq_iff int_Suc)
       
   134 done
       
   135 
       
   136 lemma Suc_nat_number_of_add:
       
   137      "Suc (number_of v + n) =  
       
   138         (if neg (number_of v :: int) then 1+n else number_of (Int.succ v) + n)"
       
   139   unfolding nat_number_of_def number_of_is_id neg_def numeral_simps
       
   140   by (simp add: Suc_nat_eq_nat_zadd1 add_ac)
       
   141 
       
   142 lemma Suc_nat_number_of [simp]:
       
   143      "Suc (number_of v) =  
       
   144         (if neg (number_of v :: int) then 1 else number_of (Int.succ v))"
       
   145 apply (cut_tac n = 0 in Suc_nat_number_of_add)
       
   146 apply (simp cong del: if_weak_cong)
       
   147 done
       
   148 
       
   149 
       
   150 subsubsection{*Addition *}
       
   151 
       
   152 lemma add_nat_number_of [simp]:
       
   153      "(number_of v :: nat) + number_of v' =  
       
   154          (if v < Int.Pls then number_of v'  
       
   155           else if v' < Int.Pls then number_of v  
       
   156           else number_of (v + v'))"
       
   157   unfolding nat_number_of_def number_of_is_id numeral_simps
       
   158   by (simp add: nat_add_distrib)
       
   159 
       
   160 lemma nat_number_of_add_1 [simp]:
       
   161   "number_of v + (1::nat) =
       
   162     (if v < Int.Pls then 1 else number_of (Int.succ v))"
       
   163   unfolding nat_number_of_def number_of_is_id numeral_simps
       
   164   by (simp add: nat_add_distrib)
       
   165 
       
   166 lemma nat_1_add_number_of [simp]:
       
   167   "(1::nat) + number_of v =
       
   168     (if v < Int.Pls then 1 else number_of (Int.succ v))"
       
   169   unfolding nat_number_of_def number_of_is_id numeral_simps
       
   170   by (simp add: nat_add_distrib)
       
   171 
       
   172 lemma nat_1_add_1 [simp]: "1 + 1 = (2::nat)"
       
   173   by (rule int_int_eq [THEN iffD1]) simp
       
   174 
       
   175 
       
   176 subsubsection{*Subtraction *}
       
   177 
       
   178 lemma diff_nat_eq_if:
       
   179      "nat z - nat z' =  
       
   180         (if neg z' then nat z   
       
   181          else let d = z-z' in     
       
   182               if neg d then 0 else nat d)"
       
   183 by (simp add: Let_def nat_diff_distrib [symmetric] neg_eq_less_0 not_neg_eq_ge_0)
       
   184 
       
   185 
       
   186 lemma diff_nat_number_of [simp]: 
       
   187      "(number_of v :: nat) - number_of v' =  
       
   188         (if v' < Int.Pls then number_of v  
       
   189          else let d = number_of (v + uminus v') in     
       
   190               if neg d then 0 else nat d)"
       
   191   unfolding nat_number_of_def number_of_is_id numeral_simps neg_def
       
   192   by auto
       
   193 
       
   194 lemma nat_number_of_diff_1 [simp]:
       
   195   "number_of v - (1::nat) =
       
   196     (if v \<le> Int.Pls then 0 else number_of (Int.pred v))"
       
   197   unfolding nat_number_of_def number_of_is_id numeral_simps
       
   198   by auto
       
   199 
       
   200 
       
   201 subsubsection{*Multiplication *}
       
   202 
       
   203 lemma mult_nat_number_of [simp]:
       
   204      "(number_of v :: nat) * number_of v' =  
       
   205        (if v < Int.Pls then 0 else number_of (v * v'))"
       
   206   unfolding nat_number_of_def number_of_is_id numeral_simps
       
   207   by (simp add: nat_mult_distrib)
       
   208 
       
   209 
       
   210 subsubsection{*Quotient *}
       
   211 
       
   212 lemma div_nat_number_of [simp]:
       
   213      "(number_of v :: nat)  div  number_of v' =  
       
   214           (if neg (number_of v :: int) then 0  
       
   215            else nat (number_of v div number_of v'))"
       
   216   unfolding nat_number_of_def number_of_is_id neg_def
       
   217   by (simp add: nat_div_distrib)
       
   218 
       
   219 lemma one_div_nat_number_of [simp]:
       
   220      "Suc 0 div number_of v' = nat (1 div number_of v')" 
       
   221 by (simp del: nat_numeral_1_eq_1 add: numeral_1_eq_Suc_0 [symmetric]) 
       
   222 
       
   223 
       
   224 subsubsection{*Remainder *}
       
   225 
       
   226 lemma mod_nat_number_of [simp]:
       
   227      "(number_of v :: nat)  mod  number_of v' =  
       
   228         (if neg (number_of v :: int) then 0  
       
   229          else if neg (number_of v' :: int) then number_of v  
       
   230          else nat (number_of v mod number_of v'))"
       
   231   unfolding nat_number_of_def number_of_is_id neg_def
       
   232   by (simp add: nat_mod_distrib)
       
   233 
       
   234 lemma one_mod_nat_number_of [simp]:
       
   235      "Suc 0 mod number_of v' =  
       
   236         (if neg (number_of v' :: int) then Suc 0
       
   237          else nat (1 mod number_of v'))"
       
   238 by (simp del: nat_numeral_1_eq_1 add: numeral_1_eq_Suc_0 [symmetric]) 
       
   239 
       
   240 
       
   241 subsubsection{* Divisibility *}
       
   242 
       
   243 lemmas dvd_eq_mod_eq_0_number_of =
       
   244   dvd_eq_mod_eq_0 [of "number_of x" "number_of y", standard]
       
   245 
       
   246 declare dvd_eq_mod_eq_0_number_of [simp]
       
   247 
       
   248 ML
       
   249 {*
       
   250 val nat_number_of_def = thm"nat_number_of_def";
       
   251 
       
   252 val nat_number_of = thm"nat_number_of";
       
   253 val nat_numeral_0_eq_0 = thm"nat_numeral_0_eq_0";
       
   254 val nat_numeral_1_eq_1 = thm"nat_numeral_1_eq_1";
       
   255 val numeral_1_eq_Suc_0 = thm"numeral_1_eq_Suc_0";
       
   256 val numeral_2_eq_2 = thm"numeral_2_eq_2";
       
   257 val nat_div_distrib = thm"nat_div_distrib";
       
   258 val nat_mod_distrib = thm"nat_mod_distrib";
       
   259 val int_nat_number_of = thm"int_nat_number_of";
       
   260 val Suc_nat_eq_nat_zadd1 = thm"Suc_nat_eq_nat_zadd1";
       
   261 val Suc_nat_number_of_add = thm"Suc_nat_number_of_add";
       
   262 val Suc_nat_number_of = thm"Suc_nat_number_of";
       
   263 val add_nat_number_of = thm"add_nat_number_of";
       
   264 val diff_nat_eq_if = thm"diff_nat_eq_if";
       
   265 val diff_nat_number_of = thm"diff_nat_number_of";
       
   266 val mult_nat_number_of = thm"mult_nat_number_of";
       
   267 val div_nat_number_of = thm"div_nat_number_of";
       
   268 val mod_nat_number_of = thm"mod_nat_number_of";
       
   269 *}
       
   270 
       
   271 
       
   272 subsection{*Comparisons*}
       
   273 
       
   274 subsubsection{*Equals (=) *}
       
   275 
       
   276 lemma eq_nat_nat_iff:
       
   277      "[| (0::int) <= z;  0 <= z' |] ==> (nat z = nat z') = (z=z')"
       
   278 by (auto elim!: nonneg_eq_int)
       
   279 
       
   280 lemma eq_nat_number_of [simp]:
       
   281      "((number_of v :: nat) = number_of v') =  
       
   282       (if neg (number_of v :: int) then (number_of v' :: int) \<le> 0
       
   283        else if neg (number_of v' :: int) then (number_of v :: int) = 0
       
   284        else v = v')"
       
   285   unfolding nat_number_of_def number_of_is_id neg_def
       
   286   by auto
       
   287 
       
   288 
       
   289 subsubsection{*Less-than (<) *}
       
   290 
       
   291 lemma less_nat_number_of [simp]:
       
   292   "(number_of v :: nat) < number_of v' \<longleftrightarrow>
       
   293     (if v < v' then Int.Pls < v' else False)"
       
   294   unfolding nat_number_of_def number_of_is_id numeral_simps
       
   295   by auto
       
   296 
       
   297 
       
   298 subsubsection{*Less-than-or-equal *}
       
   299 
       
   300 lemma le_nat_number_of [simp]:
       
   301   "(number_of v :: nat) \<le> number_of v' \<longleftrightarrow>
       
   302     (if v \<le> v' then True else v \<le> Int.Pls)"
       
   303   unfolding nat_number_of_def number_of_is_id numeral_simps
       
   304   by auto
       
   305 
       
   306 (*Maps #n to n for n = 0, 1, 2*)
       
   307 lemmas numerals = nat_numeral_0_eq_0 nat_numeral_1_eq_1 numeral_2_eq_2
       
   308 
       
   309 
       
   310 subsection{*Powers with Numeric Exponents*}
       
   311 
       
   312 text{*We cannot refer to the number @{term 2} in @{text Ring_and_Field.thy}.
       
   313 We cannot prove general results about the numeral @{term "-1"}, so we have to
       
   314 use @{term "- 1"} instead.*}
       
   315 
       
   316 lemma power2_eq_square: "(a::'a::recpower)\<twosuperior> = a * a"
       
   317   by (simp add: numeral_2_eq_2 Power.power_Suc)
       
   318 
       
   319 lemma zero_power2 [simp]: "(0::'a::{semiring_1,recpower})\<twosuperior> = 0"
       
   320   by (simp add: power2_eq_square)
       
   321 
       
   322 lemma one_power2 [simp]: "(1::'a::{semiring_1,recpower})\<twosuperior> = 1"
       
   323   by (simp add: power2_eq_square)
       
   324 
       
   325 lemma power3_eq_cube: "(x::'a::recpower) ^ 3 = x * x * x"
       
   326   apply (subgoal_tac "3 = Suc (Suc (Suc 0))")
       
   327   apply (erule ssubst)
       
   328   apply (simp add: power_Suc mult_ac)
       
   329   apply (unfold nat_number_of_def)
       
   330   apply (subst nat_eq_iff)
       
   331   apply simp
       
   332 done
       
   333 
       
   334 text{*Squares of literal numerals will be evaluated.*}
       
   335 lemmas power2_eq_square_number_of =
       
   336     power2_eq_square [of "number_of w", standard]
       
   337 declare power2_eq_square_number_of [simp]
       
   338 
       
   339 
       
   340 lemma zero_le_power2[simp]: "0 \<le> (a\<twosuperior>::'a::{ordered_idom,recpower})"
       
   341   by (simp add: power2_eq_square)
       
   342 
       
   343 lemma zero_less_power2[simp]:
       
   344      "(0 < a\<twosuperior>) = (a \<noteq> (0::'a::{ordered_idom,recpower}))"
       
   345   by (force simp add: power2_eq_square zero_less_mult_iff linorder_neq_iff)
       
   346 
       
   347 lemma power2_less_0[simp]:
       
   348   fixes a :: "'a::{ordered_idom,recpower}"
       
   349   shows "~ (a\<twosuperior> < 0)"
       
   350 by (force simp add: power2_eq_square mult_less_0_iff) 
       
   351 
       
   352 lemma zero_eq_power2[simp]:
       
   353      "(a\<twosuperior> = 0) = (a = (0::'a::{ordered_idom,recpower}))"
       
   354   by (force simp add: power2_eq_square mult_eq_0_iff)
       
   355 
       
   356 lemma abs_power2[simp]:
       
   357      "abs(a\<twosuperior>) = (a\<twosuperior>::'a::{ordered_idom,recpower})"
       
   358   by (simp add: power2_eq_square abs_mult abs_mult_self)
       
   359 
       
   360 lemma power2_abs[simp]:
       
   361      "(abs a)\<twosuperior> = (a\<twosuperior>::'a::{ordered_idom,recpower})"
       
   362   by (simp add: power2_eq_square abs_mult_self)
       
   363 
       
   364 lemma power2_minus[simp]:
       
   365      "(- a)\<twosuperior> = (a\<twosuperior>::'a::{comm_ring_1,recpower})"
       
   366   by (simp add: power2_eq_square)
       
   367 
       
   368 lemma power2_le_imp_le:
       
   369   fixes x y :: "'a::{ordered_semidom,recpower}"
       
   370   shows "\<lbrakk>x\<twosuperior> \<le> y\<twosuperior>; 0 \<le> y\<rbrakk> \<Longrightarrow> x \<le> y"
       
   371 unfolding numeral_2_eq_2 by (rule power_le_imp_le_base)
       
   372 
       
   373 lemma power2_less_imp_less:
       
   374   fixes x y :: "'a::{ordered_semidom,recpower}"
       
   375   shows "\<lbrakk>x\<twosuperior> < y\<twosuperior>; 0 \<le> y\<rbrakk> \<Longrightarrow> x < y"
       
   376 by (rule power_less_imp_less_base)
       
   377 
       
   378 lemma power2_eq_imp_eq:
       
   379   fixes x y :: "'a::{ordered_semidom,recpower}"
       
   380   shows "\<lbrakk>x\<twosuperior> = y\<twosuperior>; 0 \<le> x; 0 \<le> y\<rbrakk> \<Longrightarrow> x = y"
       
   381 unfolding numeral_2_eq_2 by (erule (2) power_eq_imp_eq_base, simp)
       
   382 
       
   383 lemma power_minus1_even[simp]: "(- 1) ^ (2*n) = (1::'a::{comm_ring_1,recpower})"
       
   384 proof (induct n)
       
   385   case 0 show ?case by simp
       
   386 next
       
   387   case (Suc n) then show ?case by (simp add: power_Suc power_add)
       
   388 qed
       
   389 
       
   390 lemma power_minus1_odd: "(- 1) ^ Suc(2*n) = -(1::'a::{comm_ring_1,recpower})"
       
   391   by (simp add: power_Suc) 
       
   392 
       
   393 lemma power_even_eq: "(a::'a::recpower) ^ (2*n) = (a^n)^2"
       
   394 by (subst mult_commute) (simp add: power_mult)
       
   395 
       
   396 lemma power_odd_eq: "(a::int) ^ Suc(2*n) = a * (a^n)^2"
       
   397 by (simp add: power_even_eq) 
       
   398 
       
   399 lemma power_minus_even [simp]:
       
   400      "(-a) ^ (2*n) = (a::'a::{comm_ring_1,recpower}) ^ (2*n)"
       
   401 by (simp add: power_minus1_even power_minus [of a]) 
       
   402 
       
   403 lemma zero_le_even_power'[simp]:
       
   404      "0 \<le> (a::'a::{ordered_idom,recpower}) ^ (2*n)"
       
   405 proof (induct "n")
       
   406   case 0
       
   407     show ?case by (simp add: zero_le_one)
       
   408 next
       
   409   case (Suc n)
       
   410     have "a ^ (2 * Suc n) = (a*a) * a ^ (2*n)" 
       
   411       by (simp add: mult_ac power_add power2_eq_square)
       
   412     thus ?case
       
   413       by (simp add: prems zero_le_mult_iff)
       
   414 qed
       
   415 
       
   416 lemma odd_power_less_zero:
       
   417      "(a::'a::{ordered_idom,recpower}) < 0 ==> a ^ Suc(2*n) < 0"
       
   418 proof (induct "n")
       
   419   case 0
       
   420   then show ?case by simp
       
   421 next
       
   422   case (Suc n)
       
   423   have "a ^ Suc (2 * Suc n) = (a*a) * a ^ Suc(2*n)"
       
   424     by (simp add: mult_ac power_add power2_eq_square)
       
   425   thus ?case
       
   426     by (simp del: power_Suc add: prems mult_less_0_iff mult_neg_neg)
       
   427 qed
       
   428 
       
   429 lemma odd_0_le_power_imp_0_le:
       
   430      "0 \<le> a  ^ Suc(2*n) ==> 0 \<le> (a::'a::{ordered_idom,recpower})"
       
   431 apply (insert odd_power_less_zero [of a n]) 
       
   432 apply (force simp add: linorder_not_less [symmetric]) 
       
   433 done
       
   434 
       
   435 text{*Simprules for comparisons where common factors can be cancelled.*}
       
   436 lemmas zero_compare_simps =
       
   437     add_strict_increasing add_strict_increasing2 add_increasing
       
   438     zero_le_mult_iff zero_le_divide_iff 
       
   439     zero_less_mult_iff zero_less_divide_iff 
       
   440     mult_le_0_iff divide_le_0_iff 
       
   441     mult_less_0_iff divide_less_0_iff 
       
   442     zero_le_power2 power2_less_0
       
   443 
       
   444 subsubsection{*Nat *}
       
   445 
       
   446 lemma Suc_pred': "0 < n ==> n = Suc(n - 1)"
       
   447 by (simp add: numerals)
       
   448 
       
   449 (*Expresses a natural number constant as the Suc of another one.
       
   450   NOT suitable for rewriting because n recurs in the condition.*)
       
   451 lemmas expand_Suc = Suc_pred' [of "number_of v", standard]
       
   452 
       
   453 subsubsection{*Arith *}
       
   454 
       
   455 lemma Suc_eq_add_numeral_1: "Suc n = n + 1"
       
   456 by (simp add: numerals)
       
   457 
       
   458 lemma Suc_eq_add_numeral_1_left: "Suc n = 1 + n"
       
   459 by (simp add: numerals)
       
   460 
       
   461 (* These two can be useful when m = number_of... *)
       
   462 
       
   463 lemma add_eq_if: "(m::nat) + n = (if m=0 then n else Suc ((m - 1) + n))"
       
   464   unfolding One_nat_def by (cases m) simp_all
       
   465 
       
   466 lemma mult_eq_if: "(m::nat) * n = (if m=0 then 0 else n + ((m - 1) * n))"
       
   467   unfolding One_nat_def by (cases m) simp_all
       
   468 
       
   469 lemma power_eq_if: "(p ^ m :: nat) = (if m=0 then 1 else p * (p ^ (m - 1)))"
       
   470   unfolding One_nat_def by (cases m) simp_all
       
   471 
       
   472 
       
   473 subsection{*Comparisons involving (0::nat) *}
       
   474 
       
   475 text{*Simplification already does @{term "n<0"}, @{term "n\<le>0"} and @{term "0\<le>n"}.*}
       
   476 
       
   477 lemma eq_number_of_0 [simp]:
       
   478   "number_of v = (0::nat) \<longleftrightarrow> v \<le> Int.Pls"
       
   479   unfolding nat_number_of_def number_of_is_id numeral_simps
       
   480   by auto
       
   481 
       
   482 lemma eq_0_number_of [simp]:
       
   483   "(0::nat) = number_of v \<longleftrightarrow> v \<le> Int.Pls"
       
   484 by (rule trans [OF eq_sym_conv eq_number_of_0])
       
   485 
       
   486 lemma less_0_number_of [simp]:
       
   487    "(0::nat) < number_of v \<longleftrightarrow> Int.Pls < v"
       
   488   unfolding nat_number_of_def number_of_is_id numeral_simps
       
   489   by simp
       
   490 
       
   491 lemma neg_imp_number_of_eq_0: "neg (number_of v :: int) ==> number_of v = (0::nat)"
       
   492 by (simp del: nat_numeral_0_eq_0 add: nat_numeral_0_eq_0 [symmetric])
       
   493 
       
   494 
       
   495 
       
   496 subsection{*Comparisons involving  @{term Suc} *}
       
   497 
       
   498 lemma eq_number_of_Suc [simp]:
       
   499      "(number_of v = Suc n) =  
       
   500         (let pv = number_of (Int.pred v) in  
       
   501          if neg pv then False else nat pv = n)"
       
   502 apply (simp only: simp_thms Let_def neg_eq_less_0 linorder_not_less 
       
   503                   number_of_pred nat_number_of_def 
       
   504             split add: split_if)
       
   505 apply (rule_tac x = "number_of v" in spec)
       
   506 apply (auto simp add: nat_eq_iff)
       
   507 done
       
   508 
       
   509 lemma Suc_eq_number_of [simp]:
       
   510      "(Suc n = number_of v) =  
       
   511         (let pv = number_of (Int.pred v) in  
       
   512          if neg pv then False else nat pv = n)"
       
   513 by (rule trans [OF eq_sym_conv eq_number_of_Suc])
       
   514 
       
   515 lemma less_number_of_Suc [simp]:
       
   516      "(number_of v < Suc n) =  
       
   517         (let pv = number_of (Int.pred v) in  
       
   518          if neg pv then True else nat pv < n)"
       
   519 apply (simp only: simp_thms Let_def neg_eq_less_0 linorder_not_less 
       
   520                   number_of_pred nat_number_of_def  
       
   521             split add: split_if)
       
   522 apply (rule_tac x = "number_of v" in spec)
       
   523 apply (auto simp add: nat_less_iff)
       
   524 done
       
   525 
       
   526 lemma less_Suc_number_of [simp]:
       
   527      "(Suc n < number_of v) =  
       
   528         (let pv = number_of (Int.pred v) in  
       
   529          if neg pv then False else n < nat pv)"
       
   530 apply (simp only: simp_thms Let_def neg_eq_less_0 linorder_not_less 
       
   531                   number_of_pred nat_number_of_def
       
   532             split add: split_if)
       
   533 apply (rule_tac x = "number_of v" in spec)
       
   534 apply (auto simp add: zless_nat_eq_int_zless)
       
   535 done
       
   536 
       
   537 lemma le_number_of_Suc [simp]:
       
   538      "(number_of v <= Suc n) =  
       
   539         (let pv = number_of (Int.pred v) in  
       
   540          if neg pv then True else nat pv <= n)"
       
   541 by (simp add: Let_def less_Suc_number_of linorder_not_less [symmetric])
       
   542 
       
   543 lemma le_Suc_number_of [simp]:
       
   544      "(Suc n <= number_of v) =  
       
   545         (let pv = number_of (Int.pred v) in  
       
   546          if neg pv then False else n <= nat pv)"
       
   547 by (simp add: Let_def less_number_of_Suc linorder_not_less [symmetric])
       
   548 
       
   549 
       
   550 lemma eq_number_of_Pls_Min: "(Numeral0 ::int) ~= number_of Int.Min"
       
   551 by auto
       
   552 
       
   553 
       
   554 
       
   555 subsection{*Max and Min Combined with @{term Suc} *}
       
   556 
       
   557 lemma max_number_of_Suc [simp]:
       
   558      "max (Suc n) (number_of v) =  
       
   559         (let pv = number_of (Int.pred v) in  
       
   560          if neg pv then Suc n else Suc(max n (nat pv)))"
       
   561 apply (simp only: Let_def neg_eq_less_0 number_of_pred nat_number_of_def 
       
   562             split add: split_if nat.split)
       
   563 apply (rule_tac x = "number_of v" in spec) 
       
   564 apply auto
       
   565 done
       
   566  
       
   567 lemma max_Suc_number_of [simp]:
       
   568      "max (number_of v) (Suc n) =  
       
   569         (let pv = number_of (Int.pred v) in  
       
   570          if neg pv then Suc n else Suc(max (nat pv) n))"
       
   571 apply (simp only: Let_def neg_eq_less_0 number_of_pred nat_number_of_def 
       
   572             split add: split_if nat.split)
       
   573 apply (rule_tac x = "number_of v" in spec) 
       
   574 apply auto
       
   575 done
       
   576  
       
   577 lemma min_number_of_Suc [simp]:
       
   578      "min (Suc n) (number_of v) =  
       
   579         (let pv = number_of (Int.pred v) in  
       
   580          if neg pv then 0 else Suc(min n (nat pv)))"
       
   581 apply (simp only: Let_def neg_eq_less_0 number_of_pred nat_number_of_def 
       
   582             split add: split_if nat.split)
       
   583 apply (rule_tac x = "number_of v" in spec) 
       
   584 apply auto
       
   585 done
       
   586  
       
   587 lemma min_Suc_number_of [simp]:
       
   588      "min (number_of v) (Suc n) =  
       
   589         (let pv = number_of (Int.pred v) in  
       
   590          if neg pv then 0 else Suc(min (nat pv) n))"
       
   591 apply (simp only: Let_def neg_eq_less_0 number_of_pred nat_number_of_def 
       
   592             split add: split_if nat.split)
       
   593 apply (rule_tac x = "number_of v" in spec) 
       
   594 apply auto
       
   595 done
       
   596  
       
   597 subsection{*Literal arithmetic involving powers*}
       
   598 
       
   599 lemma nat_power_eq: "(0::int) <= z ==> nat (z^n) = nat z ^ n"
       
   600 apply (induct "n")
       
   601 apply (simp_all (no_asm_simp) add: nat_mult_distrib)
       
   602 done
       
   603 
       
   604 lemma power_nat_number_of:
       
   605      "(number_of v :: nat) ^ n =  
       
   606        (if neg (number_of v :: int) then 0^n else nat ((number_of v :: int) ^ n))"
       
   607 by (simp only: simp_thms neg_nat not_neg_eq_ge_0 nat_number_of_def nat_power_eq
       
   608          split add: split_if cong: imp_cong)
       
   609 
       
   610 
       
   611 lemmas power_nat_number_of_number_of = power_nat_number_of [of _ "number_of w", standard]
       
   612 declare power_nat_number_of_number_of [simp]
       
   613 
       
   614 
       
   615 
       
   616 text{*For arbitrary rings*}
       
   617 
       
   618 lemma power_number_of_even:
       
   619   fixes z :: "'a::{number_ring,recpower}"
       
   620   shows "z ^ number_of (Int.Bit0 w) = (let w = z ^ (number_of w) in w * w)"
       
   621 unfolding Let_def nat_number_of_def number_of_Bit0
       
   622 apply (rule_tac x = "number_of w" in spec, clarify)
       
   623 apply (case_tac " (0::int) <= x")
       
   624 apply (auto simp add: nat_mult_distrib power_even_eq power2_eq_square)
       
   625 done
       
   626 
       
   627 lemma power_number_of_odd:
       
   628   fixes z :: "'a::{number_ring,recpower}"
       
   629   shows "z ^ number_of (Int.Bit1 w) = (if (0::int) <= number_of w
       
   630      then (let w = z ^ (number_of w) in z * w * w) else 1)"
       
   631 unfolding Let_def nat_number_of_def number_of_Bit1
       
   632 apply (rule_tac x = "number_of w" in spec, auto)
       
   633 apply (simp only: nat_add_distrib nat_mult_distrib)
       
   634 apply simp
       
   635 apply (auto simp add: nat_add_distrib nat_mult_distrib power_even_eq power2_eq_square neg_nat power_Suc)
       
   636 done
       
   637 
       
   638 lemmas zpower_number_of_even = power_number_of_even [where 'a=int]
       
   639 lemmas zpower_number_of_odd = power_number_of_odd [where 'a=int]
       
   640 
       
   641 lemmas power_number_of_even_number_of [simp] =
       
   642     power_number_of_even [of "number_of v", standard]
       
   643 
       
   644 lemmas power_number_of_odd_number_of [simp] =
       
   645     power_number_of_odd [of "number_of v", standard]
       
   646 
       
   647 
       
   648 
       
   649 ML
       
   650 {*
       
   651 val numeral_ss = @{simpset} addsimps @{thms numerals};
       
   652 
       
   653 val nat_bin_arith_setup =
       
   654  Lin_Arith.map_data
       
   655    (fn {add_mono_thms, mult_mono_thms, inj_thms, lessD, neqE, simpset} =>
       
   656      {add_mono_thms = add_mono_thms, mult_mono_thms = mult_mono_thms,
       
   657       inj_thms = inj_thms,
       
   658       lessD = lessD, neqE = neqE,
       
   659       simpset = simpset addsimps @{thms neg_simps} @
       
   660         [@{thm Suc_nat_number_of}, @{thm int_nat_number_of}]})
       
   661 *}
       
   662 
       
   663 declaration {* K nat_bin_arith_setup *}
       
   664 
       
   665 (* Enable arith to deal with div/mod k where k is a numeral: *)
       
   666 declare split_div[of _ _ "number_of k", standard, arith_split]
       
   667 declare split_mod[of _ _ "number_of k", standard, arith_split]
       
   668 
       
   669 lemma nat_number_of_Pls: "Numeral0 = (0::nat)"
       
   670   by (simp add: number_of_Pls nat_number_of_def)
       
   671 
       
   672 lemma nat_number_of_Min: "number_of Int.Min = (0::nat)"
       
   673   apply (simp only: number_of_Min nat_number_of_def nat_zminus_int)
       
   674   done
       
   675 
       
   676 lemma nat_number_of_Bit0:
       
   677     "number_of (Int.Bit0 w) = (let n::nat = number_of w in n + n)"
       
   678   unfolding nat_number_of_def number_of_is_id numeral_simps Let_def
       
   679   by auto
       
   680 
       
   681 lemma nat_number_of_Bit1:
       
   682   "number_of (Int.Bit1 w) =
       
   683     (if neg (number_of w :: int) then 0
       
   684      else let n = number_of w in Suc (n + n))"
       
   685   unfolding nat_number_of_def number_of_is_id numeral_simps neg_def Let_def
       
   686   by auto
       
   687 
       
   688 lemmas nat_number =
       
   689   nat_number_of_Pls nat_number_of_Min
       
   690   nat_number_of_Bit0 nat_number_of_Bit1
       
   691 
       
   692 lemma Let_Suc [simp]: "Let (Suc n) f == f (Suc n)"
       
   693   by (simp add: Let_def)
       
   694 
       
   695 lemma power_m1_even: "(-1) ^ (2*n) = (1::'a::{number_ring,recpower})"
       
   696 by (simp add: power_mult power_Suc); 
       
   697 
       
   698 lemma power_m1_odd: "(-1) ^ Suc(2*n) = (-1::'a::{number_ring,recpower})"
       
   699 by (simp add: power_mult power_Suc); 
       
   700 
       
   701 
       
   702 subsection{*Literal arithmetic and @{term of_nat}*}
       
   703 
       
   704 lemma of_nat_double:
       
   705      "0 \<le> x ==> of_nat (nat (2 * x)) = of_nat (nat x) + of_nat (nat x)"
       
   706 by (simp only: mult_2 nat_add_distrib of_nat_add) 
       
   707 
       
   708 lemma nat_numeral_m1_eq_0: "-1 = (0::nat)"
       
   709 by (simp only: nat_number_of_def)
       
   710 
       
   711 lemma of_nat_number_of_lemma:
       
   712      "of_nat (number_of v :: nat) =  
       
   713          (if 0 \<le> (number_of v :: int) 
       
   714           then (number_of v :: 'a :: number_ring)
       
   715           else 0)"
       
   716 by (simp add: int_number_of_def nat_number_of_def number_of_eq of_nat_nat);
       
   717 
       
   718 lemma of_nat_number_of_eq [simp]:
       
   719      "of_nat (number_of v :: nat) =  
       
   720          (if neg (number_of v :: int) then 0  
       
   721           else (number_of v :: 'a :: number_ring))"
       
   722 by (simp only: of_nat_number_of_lemma neg_def, simp) 
       
   723 
       
   724 
       
   725 subsection {*Lemmas for the Combination and Cancellation Simprocs*}
       
   726 
       
   727 lemma nat_number_of_add_left:
       
   728      "number_of v + (number_of v' + (k::nat)) =  
       
   729          (if neg (number_of v :: int) then number_of v' + k  
       
   730           else if neg (number_of v' :: int) then number_of v + k  
       
   731           else number_of (v + v') + k)"
       
   732   unfolding nat_number_of_def number_of_is_id neg_def
       
   733   by auto
       
   734 
       
   735 lemma nat_number_of_mult_left:
       
   736      "number_of v * (number_of v' * (k::nat)) =  
       
   737          (if v < Int.Pls then 0
       
   738           else number_of (v * v') * k)"
       
   739 by simp
       
   740 
       
   741 
       
   742 subsubsection{*For @{text combine_numerals}*}
       
   743 
       
   744 lemma left_add_mult_distrib: "i*u + (j*u + k) = (i+j)*u + (k::nat)"
       
   745 by (simp add: add_mult_distrib)
       
   746 
       
   747 
       
   748 subsubsection{*For @{text cancel_numerals}*}
       
   749 
       
   750 lemma nat_diff_add_eq1:
       
   751      "j <= (i::nat) ==> ((i*u + m) - (j*u + n)) = (((i-j)*u + m) - n)"
       
   752 by (simp split add: nat_diff_split add: add_mult_distrib)
       
   753 
       
   754 lemma nat_diff_add_eq2:
       
   755      "i <= (j::nat) ==> ((i*u + m) - (j*u + n)) = (m - ((j-i)*u + n))"
       
   756 by (simp split add: nat_diff_split add: add_mult_distrib)
       
   757 
       
   758 lemma nat_eq_add_iff1:
       
   759      "j <= (i::nat) ==> (i*u + m = j*u + n) = ((i-j)*u + m = n)"
       
   760 by (auto split add: nat_diff_split simp add: add_mult_distrib)
       
   761 
       
   762 lemma nat_eq_add_iff2:
       
   763      "i <= (j::nat) ==> (i*u + m = j*u + n) = (m = (j-i)*u + n)"
       
   764 by (auto split add: nat_diff_split simp add: add_mult_distrib)
       
   765 
       
   766 lemma nat_less_add_iff1:
       
   767      "j <= (i::nat) ==> (i*u + m < j*u + n) = ((i-j)*u + m < n)"
       
   768 by (auto split add: nat_diff_split simp add: add_mult_distrib)
       
   769 
       
   770 lemma nat_less_add_iff2:
       
   771      "i <= (j::nat) ==> (i*u + m < j*u + n) = (m < (j-i)*u + n)"
       
   772 by (auto split add: nat_diff_split simp add: add_mult_distrib)
       
   773 
       
   774 lemma nat_le_add_iff1:
       
   775      "j <= (i::nat) ==> (i*u + m <= j*u + n) = ((i-j)*u + m <= n)"
       
   776 by (auto split add: nat_diff_split simp add: add_mult_distrib)
       
   777 
       
   778 lemma nat_le_add_iff2:
       
   779      "i <= (j::nat) ==> (i*u + m <= j*u + n) = (m <= (j-i)*u + n)"
       
   780 by (auto split add: nat_diff_split simp add: add_mult_distrib)
       
   781 
       
   782 
       
   783 subsubsection{*For @{text cancel_numeral_factors} *}
       
   784 
       
   785 lemma nat_mult_le_cancel1: "(0::nat) < k ==> (k*m <= k*n) = (m<=n)"
       
   786 by auto
       
   787 
       
   788 lemma nat_mult_less_cancel1: "(0::nat) < k ==> (k*m < k*n) = (m<n)"
       
   789 by auto
       
   790 
       
   791 lemma nat_mult_eq_cancel1: "(0::nat) < k ==> (k*m = k*n) = (m=n)"
       
   792 by auto
       
   793 
       
   794 lemma nat_mult_div_cancel1: "(0::nat) < k ==> (k*m) div (k*n) = (m div n)"
       
   795 by auto
       
   796 
       
   797 lemma nat_mult_dvd_cancel_disj[simp]:
       
   798   "(k*m) dvd (k*n) = (k=0 | m dvd (n::nat))"
       
   799 by(auto simp: dvd_eq_mod_eq_0 mod_mult_distrib2[symmetric])
       
   800 
       
   801 lemma nat_mult_dvd_cancel1: "0 < k \<Longrightarrow> (k*m) dvd (k*n::nat) = (m dvd n)"
       
   802 by(auto)
       
   803 
       
   804 
       
   805 subsubsection{*For @{text cancel_factor} *}
       
   806 
       
   807 lemma nat_mult_le_cancel_disj: "(k*m <= k*n) = ((0::nat) < k --> m<=n)"
       
   808 by auto
       
   809 
       
   810 lemma nat_mult_less_cancel_disj: "(k*m < k*n) = ((0::nat) < k & m<n)"
       
   811 by auto
       
   812 
       
   813 lemma nat_mult_eq_cancel_disj: "(k*m = k*n) = (k = (0::nat) | m=n)"
       
   814 by auto
       
   815 
       
   816 lemma nat_mult_div_cancel_disj[simp]:
       
   817      "(k*m) div (k*n) = (if k = (0::nat) then 0 else m div n)"
       
   818 by (simp add: nat_mult_div_cancel1)
       
   819 
       
   820 
       
   821 subsection {* Simprocs for the Naturals *}
       
   822 
       
   823 use "Tools/nat_simprocs.ML"
       
   824 declaration {* K nat_simprocs_setup *}
       
   825 
       
   826 subsubsection{*For simplifying @{term "Suc m - K"} and  @{term "K - Suc m"}*}
       
   827 
       
   828 text{*Where K above is a literal*}
       
   829 
       
   830 lemma Suc_diff_eq_diff_pred: "Numeral0 < n ==> Suc m - n = m - (n - Numeral1)"
       
   831 by (simp add: numeral_0_eq_0 numeral_1_eq_1 split add: nat_diff_split)
       
   832 
       
   833 text {*Now just instantiating @{text n} to @{text "number_of v"} does
       
   834   the right simplification, but with some redundant inequality
       
   835   tests.*}
       
   836 lemma neg_number_of_pred_iff_0:
       
   837   "neg (number_of (Int.pred v)::int) = (number_of v = (0::nat))"
       
   838 apply (subgoal_tac "neg (number_of (Int.pred v)) = (number_of v < Suc 0) ")
       
   839 apply (simp only: less_Suc_eq_le le_0_eq)
       
   840 apply (subst less_number_of_Suc, simp)
       
   841 done
       
   842 
       
   843 text{*No longer required as a simprule because of the @{text inverse_fold}
       
   844    simproc*}
       
   845 lemma Suc_diff_number_of:
       
   846      "Int.Pls < v ==>
       
   847       Suc m - (number_of v) = m - (number_of (Int.pred v))"
       
   848 apply (subst Suc_diff_eq_diff_pred)
       
   849 apply simp
       
   850 apply (simp del: nat_numeral_1_eq_1)
       
   851 apply (auto simp only: diff_nat_number_of less_0_number_of [symmetric]
       
   852                         neg_number_of_pred_iff_0)
       
   853 done
       
   854 
       
   855 lemma diff_Suc_eq_diff_pred: "m - Suc n = (m - 1) - n"
       
   856 by (simp add: numerals split add: nat_diff_split)
       
   857 
       
   858 
       
   859 subsubsection{*For @{term nat_case} and @{term nat_rec}*}
       
   860 
       
   861 lemma nat_case_number_of [simp]:
       
   862      "nat_case a f (number_of v) =
       
   863         (let pv = number_of (Int.pred v) in
       
   864          if neg pv then a else f (nat pv))"
       
   865 by (simp split add: nat.split add: Let_def neg_number_of_pred_iff_0)
       
   866 
       
   867 lemma nat_case_add_eq_if [simp]:
       
   868      "nat_case a f ((number_of v) + n) =
       
   869        (let pv = number_of (Int.pred v) in
       
   870          if neg pv then nat_case a f n else f (nat pv + n))"
       
   871 apply (subst add_eq_if)
       
   872 apply (simp split add: nat.split
       
   873             del: nat_numeral_1_eq_1
       
   874             add: nat_numeral_1_eq_1 [symmetric]
       
   875                  numeral_1_eq_Suc_0 [symmetric]
       
   876                  neg_number_of_pred_iff_0)
       
   877 done
       
   878 
       
   879 lemma nat_rec_number_of [simp]:
       
   880      "nat_rec a f (number_of v) =
       
   881         (let pv = number_of (Int.pred v) in
       
   882          if neg pv then a else f (nat pv) (nat_rec a f (nat pv)))"
       
   883 apply (case_tac " (number_of v) ::nat")
       
   884 apply (simp_all (no_asm_simp) add: Let_def neg_number_of_pred_iff_0)
       
   885 apply (simp split add: split_if_asm)
       
   886 done
       
   887 
       
   888 lemma nat_rec_add_eq_if [simp]:
       
   889      "nat_rec a f (number_of v + n) =
       
   890         (let pv = number_of (Int.pred v) in
       
   891          if neg pv then nat_rec a f n
       
   892                    else f (nat pv + n) (nat_rec a f (nat pv + n)))"
       
   893 apply (subst add_eq_if)
       
   894 apply (simp split add: nat.split
       
   895             del: nat_numeral_1_eq_1
       
   896             add: nat_numeral_1_eq_1 [symmetric]
       
   897                  numeral_1_eq_Suc_0 [symmetric]
       
   898                  neg_number_of_pred_iff_0)
       
   899 done
       
   900 
       
   901 
       
   902 subsubsection{*Various Other Lemmas*}
       
   903 
       
   904 text {*Evens and Odds, for Mutilated Chess Board*}
       
   905 
       
   906 text{*Lemmas for specialist use, NOT as default simprules*}
       
   907 lemma nat_mult_2: "2 * z = (z+z::nat)"
       
   908 proof -
       
   909   have "2*z = (1 + 1)*z" by simp
       
   910   also have "... = z+z" by (simp add: left_distrib)
       
   911   finally show ?thesis .
       
   912 qed
       
   913 
       
   914 lemma nat_mult_2_right: "z * 2 = (z+z::nat)"
       
   915 by (subst mult_commute, rule nat_mult_2)
       
   916 
       
   917 text{*Case analysis on @{term "n<2"}*}
       
   918 lemma less_2_cases: "(n::nat) < 2 ==> n = 0 | n = Suc 0"
       
   919 by arith
       
   920 
       
   921 lemma div2_Suc_Suc [simp]: "Suc(Suc m) div 2 = Suc (m div 2)"
       
   922 by arith
       
   923 
       
   924 lemma add_self_div_2 [simp]: "(m + m) div 2 = (m::nat)"
       
   925 by (simp add: nat_mult_2 [symmetric])
       
   926 
       
   927 lemma mod2_Suc_Suc [simp]: "Suc(Suc(m)) mod 2 = m mod 2"
       
   928 apply (subgoal_tac "m mod 2 < 2")
       
   929 apply (erule less_2_cases [THEN disjE])
       
   930 apply (simp_all (no_asm_simp) add: Let_def mod_Suc nat_1)
       
   931 done
       
   932 
       
   933 lemma mod2_gr_0 [simp]: "!!m::nat. (0 < m mod 2) = (m mod 2 = 1)"
       
   934 apply (subgoal_tac "m mod 2 < 2")
       
   935 apply (force simp del: mod_less_divisor, simp)
       
   936 done
       
   937 
       
   938 text{*Removal of Small Numerals: 0, 1 and (in additive positions) 2*}
       
   939 
       
   940 lemma add_2_eq_Suc [simp]: "2 + n = Suc (Suc n)"
       
   941 by simp
       
   942 
       
   943 lemma add_2_eq_Suc' [simp]: "n + 2 = Suc (Suc n)"
       
   944 by simp
       
   945 
       
   946 text{*Can be used to eliminate long strings of Sucs, but not by default*}
       
   947 lemma Suc3_eq_add_3: "Suc (Suc (Suc n)) = 3 + n"
       
   948 by simp
       
   949 
       
   950 
       
   951 text{*These lemmas collapse some needless occurrences of Suc:
       
   952     at least three Sucs, since two and fewer are rewritten back to Suc again!
       
   953     We already have some rules to simplify operands smaller than 3.*}
       
   954 
       
   955 lemma div_Suc_eq_div_add3 [simp]: "m div (Suc (Suc (Suc n))) = m div (3+n)"
       
   956 by (simp add: Suc3_eq_add_3)
       
   957 
       
   958 lemma mod_Suc_eq_mod_add3 [simp]: "m mod (Suc (Suc (Suc n))) = m mod (3+n)"
       
   959 by (simp add: Suc3_eq_add_3)
       
   960 
       
   961 lemma Suc_div_eq_add3_div: "(Suc (Suc (Suc m))) div n = (3+m) div n"
       
   962 by (simp add: Suc3_eq_add_3)
       
   963 
       
   964 lemma Suc_mod_eq_add3_mod: "(Suc (Suc (Suc m))) mod n = (3+m) mod n"
       
   965 by (simp add: Suc3_eq_add_3)
       
   966 
       
   967 lemmas Suc_div_eq_add3_div_number_of =
       
   968     Suc_div_eq_add3_div [of _ "number_of v", standard]
       
   969 declare Suc_div_eq_add3_div_number_of [simp]
       
   970 
       
   971 lemmas Suc_mod_eq_add3_mod_number_of =
       
   972     Suc_mod_eq_add3_mod [of _ "number_of v", standard]
       
   973 declare Suc_mod_eq_add3_mod_number_of [simp]
       
   974 
       
   975 end