src/HOL/mono.ML
author paulson
Thu Sep 23 13:06:31 1999 +0200 (1999-09-23)
changeset 7584 5be4bb8e4e3f
parent 7109 b02c6bdda05b
child 7713 f4fe9d620107
permissions -rw-r--r--
tidied; added lemma restrict_to_left
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(*  Title:      HOL/mono.ML
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    ID:         $Id$
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    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
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    Copyright   1991  University of Cambridge
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Monotonicity of various operations
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*)
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Goal "A<=B ==> f``A <= f``B";
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by (Blast_tac 1);
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qed "image_mono";
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Goal "A<=B ==> Pow(A) <= Pow(B)";
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by (Blast_tac 1);
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qed "Pow_mono";
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Goal "A<=B ==> Union(A) <= Union(B)";
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by (Blast_tac 1);
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qed "Union_mono";
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Goal "B<=A ==> Inter(A) <= Inter(B)";
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by (Blast_tac 1);
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qed "Inter_anti_mono";
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val prems = Goal
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    "[| A<=B;  !!x. x:A ==> f(x)<=g(x) |] ==> \
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\    (UN x:A. f(x)) <= (UN x:B. g(x))";
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by (blast_tac (claset() addIs (prems RL [subsetD])) 1);
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qed "UN_mono";
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(*The last inclusion is POSITIVE! *)
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val prems = Goal
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    "[| B<=A;  !!x. x:A ==> f(x)<=g(x) |] ==> \
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\    (INT x:A. f(x)) <= (INT x:A. g(x))";
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by (blast_tac (claset() addIs (prems RL [subsetD])) 1);
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qed "INT_anti_mono";
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Goal "C<=D ==> insert a C <= insert a D";
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by (Blast_tac 1);
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qed "insert_mono";
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Goal "[| A<=C;  B<=D |] ==> A Un B <= C Un D";
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by (Blast_tac 1);
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qed "Un_mono";
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Goal "[| A<=C;  B<=D |] ==> A Int B <= C Int D";
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by (Blast_tac 1);
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qed "Int_mono";
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Goal "!!A::'a set. [| A<=C;  D<=B |] ==> A-B <= C-D";
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by (Blast_tac 1);
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qed "Diff_mono";
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Goal "!!A::'a set. A <= B ==> -B <= -A";
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by (Blast_tac 1);
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qed "Compl_anti_mono";
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(** Monotonicity of implications.  For inductive definitions **)
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Goal "A<=B ==> x:A --> x:B";
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by (rtac impI 1);
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by (etac subsetD 1);
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by (assume_tac 1);
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qed "in_mono";
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Goal "[| P1-->Q1; P2-->Q2 |] ==> (P1&P2) --> (Q1&Q2)";
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by (Blast_tac 1);
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qed "conj_mono";
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Goal "[| P1-->Q1; P2-->Q2 |] ==> (P1|P2) --> (Q1|Q2)";
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by (Blast_tac 1);
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qed "disj_mono";
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Goal "[| Q1-->P1; P2-->Q2 |] ==> (P1-->P2)-->(Q1-->Q2)";
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by (Blast_tac 1);
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qed "imp_mono";
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Goal "P-->P";
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by (rtac impI 1);
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by (assume_tac 1);
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qed "imp_refl";
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val [PQimp] = Goal
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    "[| !!x. P(x) --> Q(x) |] ==> (EX x. P(x)) --> (EX x. Q(x))";
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by (blast_tac (claset() addIs [PQimp RS mp]) 1);
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qed "ex_mono";
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val [PQimp] = Goal
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    "[| !!x. P(x) --> Q(x) |] ==> (ALL x. P(x)) --> (ALL x. Q(x))";
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by (blast_tac (claset() addIs [PQimp RS mp]) 1);
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qed "all_mono";
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val [PQimp] = Goal
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    "[| !!x. P(x) --> Q(x) |] ==> Collect(P) <= Collect(Q)";
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by (blast_tac (claset() addIs [PQimp RS mp]) 1);
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qed "Collect_mono";
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val [subs,PQimp] = Goal
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    "[| A<=B;  !!x. x:A ==> P(x) --> Q(x) \
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\    |] ==> A Int Collect(P) <= B Int Collect(Q)";
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by (blast_tac (claset() addIs [subs RS subsetD, PQimp RS mp]) 1);
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qed "Int_Collect_mono";
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val basic_monos = [subset_refl, imp_refl, disj_mono, conj_mono, 
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                   ex_mono, Collect_mono, in_mono];
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(* Courtesy of Stephan Merz *)
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Goalw [Least_def,mono_def]
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  "[| mono (f::'a::order => 'b::order); ? x:S. ! y:S. x <= y |] \
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\  ==> (LEAST y. y : f``S) = f(LEAST x. x : S)";
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by (etac bexE 1);
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by (rtac selectI2 1);
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by (Force_tac 1);
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by (rtac select_equality 1);
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by (Force_tac 1);
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by (force_tac (claset() addSIs [order_antisym], simpset()) 1);
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qed "Least_mono";