diff -r ca430e6aee1c -r 9b535493ac8d src/HOL/NumberTheory/WilsonBij.thy --- a/src/HOL/NumberTheory/WilsonBij.thy Tue Sep 29 22:15:54 2009 +0200 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,263 +0,0 @@ -(* Title: HOL/NumberTheory/WilsonBij.thy - ID: $Id$ - Author: Thomas M. Rasmussen - Copyright 2000 University of Cambridge -*) - -header {* Wilson's Theorem using a more abstract approach *} - -theory WilsonBij imports BijectionRel IntFact begin - -text {* - Wilson's Theorem using a more ``abstract'' approach based on - bijections between sets. Does not use Fermat's Little Theorem - (unlike Russinoff). -*} - - -subsection {* Definitions and lemmas *} - -definition - reciR :: "int => int => int => bool" where - "reciR p = (\a b. zcong (a * b) 1 p \ 1 < a \ a < p - 1 \ 1 < b \ b < p - 1)" - -definition - inv :: "int => int => int" where - "inv p a = - (if zprime p \ 0 < a \ a < p then - (SOME x. 0 \ x \ x < p \ zcong (a * x) 1 p) - else 0)" - - -text {* \medskip Inverse *} - -lemma inv_correct: - "zprime p ==> 0 < a ==> a < p - ==> 0 \ inv p a \ inv p a < p \ [a * inv p a = 1] (mod p)" - apply (unfold inv_def) - apply (simp (no_asm_simp)) - apply (rule zcong_lineq_unique [THEN ex1_implies_ex, THEN someI_ex]) - apply (erule_tac [2] zless_zprime_imp_zrelprime) - apply (unfold zprime_def) - apply auto - done - -lemmas inv_ge = inv_correct [THEN conjunct1, standard] -lemmas inv_less = inv_correct [THEN conjunct2, THEN conjunct1, standard] -lemmas inv_is_inv = inv_correct [THEN conjunct2, THEN conjunct2, standard] - -lemma inv_not_0: - "zprime p ==> 1 < a ==> a < p - 1 ==> inv p a \ 0" - -- {* same as @{text WilsonRuss} *} - apply safe - apply (cut_tac a = a and p = p in inv_is_inv) - apply (unfold zcong_def) - apply auto - apply (subgoal_tac "\ p dvd 1") - apply (rule_tac [2] zdvd_not_zless) - apply (subgoal_tac "p dvd 1") - prefer 2 - apply (subst dvd_minus_iff [symmetric]) - apply auto - done - -lemma inv_not_1: - "zprime p ==> 1 < a ==> a < p - 1 ==> inv p a \ 1" - -- {* same as @{text WilsonRuss} *} - apply safe - apply (cut_tac a = a and p = p in inv_is_inv) - prefer 4 - apply simp - apply (subgoal_tac "a = 1") - apply (rule_tac [2] zcong_zless_imp_eq) - apply auto - done - -lemma aux: "[a * (p - 1) = 1] (mod p) = [a = p - 1] (mod p)" - -- {* same as @{text WilsonRuss} *} - apply (unfold zcong_def) - apply (simp add: OrderedGroup.diff_diff_eq diff_diff_eq2 zdiff_zmult_distrib2) - apply (rule_tac s = "p dvd -((a + 1) + (p * -a))" in trans) - apply (simp add: mult_commute) - apply (subst dvd_minus_iff) - apply (subst zdvd_reduce) - apply (rule_tac s = "p dvd (a + 1) + (p * -1)" in trans) - apply (subst zdvd_reduce) - apply auto - done - -lemma inv_not_p_minus_1: - "zprime p ==> 1 < a ==> a < p - 1 ==> inv p a \ p - 1" - -- {* same as @{text WilsonRuss} *} - apply safe - apply (cut_tac a = a and p = p in inv_is_inv) - apply auto - apply (simp add: aux) - apply (subgoal_tac "a = p - 1") - apply (rule_tac [2] zcong_zless_imp_eq) - apply auto - done - -text {* - Below is slightly different as we don't expand @{term [source] inv} - but use ``@{text correct}'' theorems. -*} - -lemma inv_g_1: "zprime p ==> 1 < a ==> a < p - 1 ==> 1 < inv p a" - apply (subgoal_tac "inv p a \ 1") - apply (subgoal_tac "inv p a \ 0") - apply (subst order_less_le) - apply (subst zle_add1_eq_le [symmetric]) - apply (subst order_less_le) - apply (rule_tac [2] inv_not_0) - apply (rule_tac [5] inv_not_1) - apply auto - apply (rule inv_ge) - apply auto - done - -lemma inv_less_p_minus_1: - "zprime p ==> 1 < a ==> a < p - 1 ==> inv p a < p - 1" - -- {* ditto *} - apply (subst order_less_le) - apply (simp add: inv_not_p_minus_1 inv_less) - done - - -text {* \medskip Bijection *} - -lemma aux1: "1 < x ==> 0 \ (x::int)" - apply auto - done - -lemma aux2: "1 < x ==> 0 < (x::int)" - apply auto - done - -lemma aux3: "x \ p - 2 ==> x < (p::int)" - apply auto - done - -lemma aux4: "x \ p - 2 ==> x < (p::int) - 1" - apply auto - done - -lemma inv_inj: "zprime p ==> inj_on (inv p) (d22set (p - 2))" - apply (unfold inj_on_def) - apply auto - apply (rule zcong_zless_imp_eq) - apply (tactic {* stac (thm "zcong_cancel" RS sym) 5 *}) - apply (rule_tac [7] zcong_trans) - apply (tactic {* stac (thm "zcong_sym") 8 *}) - apply (erule_tac [7] inv_is_inv) - apply (tactic "asm_simp_tac @{simpset} 9") - apply (erule_tac [9] inv_is_inv) - apply (rule_tac [6] zless_zprime_imp_zrelprime) - apply (rule_tac [8] inv_less) - apply (rule_tac [7] inv_g_1 [THEN aux2]) - apply (unfold zprime_def) - apply (auto intro: d22set_g_1 d22set_le - aux1 aux2 aux3 aux4) - done - -lemma inv_d22set_d22set: - "zprime p ==> inv p ` d22set (p - 2) = d22set (p - 2)" - apply (rule endo_inj_surj) - apply (rule d22set_fin) - apply (erule_tac [2] inv_inj) - apply auto - apply (rule d22set_mem) - apply (erule inv_g_1) - apply (subgoal_tac [3] "inv p xa < p - 1") - apply (erule_tac [4] inv_less_p_minus_1) - apply (auto intro: d22set_g_1 d22set_le aux4) - done - -lemma d22set_d22set_bij: - "zprime p ==> (d22set (p - 2), d22set (p - 2)) \ bijR (reciR p)" - apply (unfold reciR_def) - apply (rule_tac s = "(d22set (p - 2), inv p ` d22set (p - 2))" in subst) - apply (simp add: inv_d22set_d22set) - apply (rule inj_func_bijR) - apply (rule_tac [3] d22set_fin) - apply (erule_tac [2] inv_inj) - apply auto - apply (erule inv_is_inv) - apply (erule_tac [5] inv_g_1) - apply (erule_tac [7] inv_less_p_minus_1) - apply (auto intro: d22set_g_1 d22set_le aux2 aux3 aux4) - done - -lemma reciP_bijP: "zprime p ==> bijP (reciR p) (d22set (p - 2))" - apply (unfold reciR_def bijP_def) - apply auto - apply (rule d22set_mem) - apply auto - done - -lemma reciP_uniq: "zprime p ==> uniqP (reciR p)" - apply (unfold reciR_def uniqP_def) - apply auto - apply (rule zcong_zless_imp_eq) - apply (tactic {* stac (thm "zcong_cancel2" RS sym) 5 *}) - apply (rule_tac [7] zcong_trans) - apply (tactic {* stac (thm "zcong_sym") 8 *}) - apply (rule_tac [6] zless_zprime_imp_zrelprime) - apply auto - apply (rule zcong_zless_imp_eq) - apply (tactic {* stac (thm "zcong_cancel" RS sym) 5 *}) - apply (rule_tac [7] zcong_trans) - apply (tactic {* stac (thm "zcong_sym") 8 *}) - apply (rule_tac [6] zless_zprime_imp_zrelprime) - apply auto - done - -lemma reciP_sym: "zprime p ==> symP (reciR p)" - apply (unfold reciR_def symP_def) - apply (simp add: zmult_commute) - apply auto - done - -lemma bijER_d22set: "zprime p ==> d22set (p - 2) \ bijER (reciR p)" - apply (rule bijR_bijER) - apply (erule d22set_d22set_bij) - apply (erule reciP_bijP) - apply (erule reciP_uniq) - apply (erule reciP_sym) - done - - -subsection {* Wilson *} - -lemma bijER_zcong_prod_1: - "zprime p ==> A \ bijER (reciR p) ==> [\A = 1] (mod p)" - apply (unfold reciR_def) - apply (erule bijER.induct) - apply (subgoal_tac [2] "a = 1 \ a = p - 1") - apply (rule_tac [3] zcong_square_zless) - apply auto - apply (subst setprod_insert) - prefer 3 - apply (subst setprod_insert) - apply (auto simp add: fin_bijER) - apply (subgoal_tac "zcong ((a * b) * \A) (1 * 1) p") - apply (simp add: zmult_assoc) - apply (rule zcong_zmult) - apply auto - done - -theorem Wilson_Bij: "zprime p ==> [zfact (p - 1) = -1] (mod p)" - apply (subgoal_tac "zcong ((p - 1) * zfact (p - 2)) (-1 * 1) p") - apply (rule_tac [2] zcong_zmult) - apply (simp add: zprime_def) - apply (subst zfact.simps) - apply (rule_tac t = "p - 1 - 1" and s = "p - 2" in subst) - apply auto - apply (simp add: zcong_def) - apply (subst d22set_prod_zfact [symmetric]) - apply (rule bijER_zcong_prod_1) - apply (rule_tac [2] bijER_d22set) - apply auto - done - -end