(* Title : Real/RealDef.ML
ID : $Id$
Author : Jacques D. Fleuriot
Copyright : 1998 University of Cambridge
Description : The reals
*)
(*** Proving that realrel is an equivalence relation ***)
Goal "[| (x1::preal) + y2 = x2 + y1; x2 + y3 = x3 + y2 |] \
\ ==> x1 + y3 = x3 + y1";
by (res_inst_tac [("C","y2")] preal_add_right_cancel 1);
by (rotate_tac 1 1 THEN dtac sym 1);
by (asm_full_simp_tac (simpset() addsimps preal_add_ac) 1);
by (rtac (preal_add_left_commute RS subst) 1);
by (res_inst_tac [("x1","x1")] (preal_add_assoc RS subst) 1);
by (asm_full_simp_tac (simpset() addsimps preal_add_ac) 1);
qed "preal_trans_lemma";
(** Natural deduction for realrel **)
Goalw [realrel_def]
"(((x1,y1),(x2,y2)): realrel) = (x1 + y2 = x2 + y1)";
by (Blast_tac 1);
qed "realrel_iff";
Goalw [realrel_def]
"[| x1 + y2 = x2 + y1 |] ==> ((x1,y1),(x2,y2)): realrel";
by (Blast_tac 1);
qed "realrelI";
Goalw [realrel_def]
"p: realrel --> (EX x1 y1 x2 y2. \
\ p = ((x1,y1),(x2,y2)) & x1 + y2 = x2 + y1)";
by (Blast_tac 1);
qed "realrelE_lemma";
val [major,minor] = Goal
"[| p: realrel; \
\ !!x1 y1 x2 y2. [| p = ((x1,y1),(x2,y2)); x1+y2 = x2+y1 \
\ |] ==> Q |] ==> Q";
by (cut_facts_tac [major RS (realrelE_lemma RS mp)] 1);
by (REPEAT (eresolve_tac [asm_rl,exE,conjE,minor] 1));
qed "realrelE";
AddSIs [realrelI];
AddSEs [realrelE];
Goal "(x,x): realrel";
by (pair_tac "x" 1);
by (rtac realrelI 1);
by (rtac refl 1);
qed "realrel_refl";
Goalw [equiv_def, refl_def, sym_def, trans_def] "equiv UNIV realrel";
by (fast_tac (claset() addSIs [realrel_refl]
addSEs [sym, preal_trans_lemma]) 1);
qed "equiv_realrel";
(* (realrel ^^ {x} = realrel ^^ {y}) = ((x,y) : realrel) *)
bind_thm ("equiv_realrel_iff",
[equiv_realrel, UNIV_I, UNIV_I] MRS eq_equiv_class_iff);
Goalw [real_def,realrel_def,quotient_def] "realrel^^{(x,y)}:real";
by (Blast_tac 1);
qed "realrel_in_real";
Goal "inj_on Abs_real real";
by (rtac inj_on_inverseI 1);
by (etac Abs_real_inverse 1);
qed "inj_on_Abs_real";
Addsimps [equiv_realrel_iff,inj_on_Abs_real RS inj_on_iff,
realrel_iff, realrel_in_real, Abs_real_inverse];
Addsimps [equiv_realrel RS eq_equiv_class_iff];
bind_thm ("eq_realrelD", equiv_realrel RSN (2,eq_equiv_class));
Goal "inj(Rep_real)";
by (rtac inj_inverseI 1);
by (rtac Rep_real_inverse 1);
qed "inj_Rep_real";
(** real_of_preal: the injection from preal to real **)
Goal "inj(real_of_preal)";
by (rtac injI 1);
by (rewtac real_of_preal_def);
by (dtac (inj_on_Abs_real RS inj_onD) 1);
by (REPEAT (rtac realrel_in_real 1));
by (dtac eq_equiv_class 1);
by (rtac equiv_realrel 1);
by (Blast_tac 1);
by Safe_tac;
by (Asm_full_simp_tac 1);
qed "inj_real_of_preal";
val [prem] = Goal
"(!!x y. z = Abs_real(realrel^^{(x,y)}) ==> P) ==> P";
by (res_inst_tac [("x1","z")]
(rewrite_rule [real_def] Rep_real RS quotientE) 1);
by (dres_inst_tac [("f","Abs_real")] arg_cong 1);
by (res_inst_tac [("p","x")] PairE 1);
by (rtac prem 1);
by (asm_full_simp_tac (simpset() addsimps [Rep_real_inverse]) 1);
qed "eq_Abs_real";
(**** real_minus: additive inverse on real ****)
Goalw [congruent_def]
"congruent realrel (%p. (%(x,y). realrel^^{(y,x)}) p)";
by (Clarify_tac 1);
by (asm_full_simp_tac (simpset() addsimps [preal_add_commute]) 1);
qed "real_minus_congruent";
Goalw [real_minus_def]
"- (Abs_real(realrel^^{(x,y)})) = Abs_real(realrel ^^ {(y,x)})";
by (res_inst_tac [("f","Abs_real")] arg_cong 1);
by (simp_tac (simpset() addsimps
[realrel_in_real RS Abs_real_inverse,
[equiv_realrel, real_minus_congruent] MRS UN_equiv_class]) 1);
qed "real_minus";
Goal "- (- z) = (z::real)";
by (res_inst_tac [("z","z")] eq_Abs_real 1);
by (asm_simp_tac (simpset() addsimps [real_minus]) 1);
qed "real_minus_minus";
Addsimps [real_minus_minus];
Goal "inj(%r::real. -r)";
by (rtac injI 1);
by (dres_inst_tac [("f","uminus")] arg_cong 1);
by (asm_full_simp_tac (simpset() addsimps [real_minus_minus]) 1);
qed "inj_real_minus";
Goalw [real_zero_def] "-0 = (0::real)";
by (simp_tac (simpset() addsimps [real_minus]) 1);
qed "real_minus_zero";
Addsimps [real_minus_zero];
Goal "(-x = 0) = (x = (0::real))";
by (res_inst_tac [("z","x")] eq_Abs_real 1);
by (auto_tac (claset(),
simpset() addsimps [real_zero_def, real_minus] @ preal_add_ac));
qed "real_minus_zero_iff";
Addsimps [real_minus_zero_iff];
(*** Congruence property for addition ***)
Goalw [congruent2_def]
"congruent2 realrel (%p1 p2. \
\ (%(x1,y1). (%(x2,y2). realrel^^{(x1+x2, y1+y2)}) p2) p1)";
by (Clarify_tac 1);
by (asm_simp_tac (simpset() addsimps [preal_add_assoc]) 1);
by (res_inst_tac [("z1.1","x1a")] (preal_add_left_commute RS ssubst) 1);
by (asm_simp_tac (simpset() addsimps [preal_add_assoc RS sym]) 1);
by (asm_simp_tac (simpset() addsimps preal_add_ac) 1);
qed "real_add_congruent2";
Goalw [real_add_def]
"Abs_real(realrel^^{(x1,y1)}) + Abs_real(realrel^^{(x2,y2)}) = \
\ Abs_real(realrel^^{(x1+x2, y1+y2)})";
by (simp_tac (simpset() addsimps
[[equiv_realrel, real_add_congruent2] MRS UN_equiv_class2]) 1);
qed "real_add";
Goal "(z::real) + w = w + z";
by (res_inst_tac [("z","z")] eq_Abs_real 1);
by (res_inst_tac [("z","w")] eq_Abs_real 1);
by (asm_simp_tac (simpset() addsimps preal_add_ac @ [real_add]) 1);
qed "real_add_commute";
Goal "((z1::real) + z2) + z3 = z1 + (z2 + z3)";
by (res_inst_tac [("z","z1")] eq_Abs_real 1);
by (res_inst_tac [("z","z2")] eq_Abs_real 1);
by (res_inst_tac [("z","z3")] eq_Abs_real 1);
by (asm_simp_tac (simpset() addsimps [real_add, preal_add_assoc]) 1);
qed "real_add_assoc";
(*For AC rewriting*)
Goal "(x::real)+(y+z)=y+(x+z)";
by (rtac (real_add_commute RS trans) 1);
by (rtac (real_add_assoc RS trans) 1);
by (rtac (real_add_commute RS arg_cong) 1);
qed "real_add_left_commute";
(* real addition is an AC operator *)
bind_thms ("real_add_ac", [real_add_assoc,real_add_commute,real_add_left_commute]);
Goalw [real_of_preal_def,real_zero_def] "(0::real) + z = z";
by (res_inst_tac [("z","z")] eq_Abs_real 1);
by (asm_full_simp_tac (simpset() addsimps [real_add] @ preal_add_ac) 1);
qed "real_add_zero_left";
Addsimps [real_add_zero_left];
Goal "z + (0::real) = z";
by (simp_tac (simpset() addsimps [real_add_commute]) 1);
qed "real_add_zero_right";
Addsimps [real_add_zero_right];
Goalw [real_zero_def] "z + (-z) = (0::real)";
by (res_inst_tac [("z","z")] eq_Abs_real 1);
by (asm_full_simp_tac (simpset() addsimps [real_minus,
real_add, preal_add_commute]) 1);
qed "real_add_minus";
Addsimps [real_add_minus];
Goal "(-z) + z = (0::real)";
by (simp_tac (simpset() addsimps [real_add_commute]) 1);
qed "real_add_minus_left";
Addsimps [real_add_minus_left];
Goal "z + ((- z) + w) = (w::real)";
by (simp_tac (simpset() addsimps [real_add_assoc RS sym]) 1);
qed "real_add_minus_cancel";
Goal "(-z) + (z + w) = (w::real)";
by (simp_tac (simpset() addsimps [real_add_assoc RS sym]) 1);
qed "real_minus_add_cancel";
Addsimps [real_add_minus_cancel, real_minus_add_cancel];
Goal "EX y. (x::real) + y = 0";
by (blast_tac (claset() addIs [real_add_minus]) 1);
qed "real_minus_ex";
Goal "EX! y. (x::real) + y = 0";
by (auto_tac (claset() addIs [real_add_minus],simpset()));
by (dres_inst_tac [("f","%x. ya+x")] arg_cong 1);
by (asm_full_simp_tac (simpset() addsimps [real_add_assoc RS sym]) 1);
by (asm_full_simp_tac (simpset() addsimps [real_add_commute]) 1);
qed "real_minus_ex1";
Goal "EX! y. y + (x::real) = 0";
by (auto_tac (claset() addIs [real_add_minus_left],simpset()));
by (dres_inst_tac [("f","%x. x+ya")] arg_cong 1);
by (asm_full_simp_tac (simpset() addsimps [real_add_assoc]) 1);
by (asm_full_simp_tac (simpset() addsimps [real_add_commute]) 1);
qed "real_minus_left_ex1";
Goal "x + y = (0::real) ==> x = -y";
by (cut_inst_tac [("z","y")] real_add_minus_left 1);
by (res_inst_tac [("x1","y")] (real_minus_left_ex1 RS ex1E) 1);
by (Blast_tac 1);
qed "real_add_minus_eq_minus";
Goal "EX (y::real). x = -y";
by (cut_inst_tac [("x","x")] real_minus_ex 1);
by (etac exE 1 THEN dtac real_add_minus_eq_minus 1);
by (Fast_tac 1);
qed "real_as_add_inverse_ex";
Goal "-(x + y) = (-x) + (- y :: real)";
by (res_inst_tac [("z","x")] eq_Abs_real 1);
by (res_inst_tac [("z","y")] eq_Abs_real 1);
by (auto_tac (claset(),simpset() addsimps [real_minus,real_add]));
qed "real_minus_add_distrib";
Addsimps [real_minus_add_distrib];
Goal "((x::real) + y = x + z) = (y = z)";
by (Step_tac 1);
by (dres_inst_tac [("f","%t. (-x) + t")] arg_cong 1);
by (asm_full_simp_tac (simpset() addsimps [real_add_assoc RS sym]) 1);
qed "real_add_left_cancel";
Goal "(y + (x::real)= z + x) = (y = z)";
by (simp_tac (simpset() addsimps [real_add_commute,real_add_left_cancel]) 1);
qed "real_add_right_cancel";
Goal "(0::real) - x = -x";
by (simp_tac (simpset() addsimps [real_diff_def]) 1);
qed "real_diff_0";
Goal "x - (0::real) = x";
by (simp_tac (simpset() addsimps [real_diff_def]) 1);
qed "real_diff_0_right";
Goal "x - x = (0::real)";
by (simp_tac (simpset() addsimps [real_diff_def]) 1);
qed "real_diff_self";
Addsimps [real_diff_0, real_diff_0_right, real_diff_self];
(*** Congruence property for multiplication ***)
Goal "!!(x1::preal). [| x1 + y2 = x2 + y1 |] ==> \
\ x * x1 + y * y1 + (x * y2 + x2 * y) = \
\ x * x2 + y * y2 + (x * y1 + x1 * y)";
by (asm_full_simp_tac (simpset() addsimps [preal_add_left_commute,
preal_add_assoc RS sym,preal_add_mult_distrib2 RS sym]) 1);
by (rtac (preal_mult_commute RS subst) 1);
by (res_inst_tac [("y1","x2")] (preal_mult_commute RS subst) 1);
by (asm_full_simp_tac (simpset() addsimps [preal_add_assoc,
preal_add_mult_distrib2 RS sym]) 1);
by (asm_full_simp_tac (simpset() addsimps [preal_add_commute]) 1);
qed "real_mult_congruent2_lemma";
Goal
"congruent2 realrel (%p1 p2. \
\ (%(x1,y1). (%(x2,y2). realrel^^{(x1*x2 + y1*y2, x1*y2+x2*y1)}) p2) p1)";
by (rtac (equiv_realrel RS congruent2_commuteI) 1);
by (Clarify_tac 1);
by (rewtac split_def);
by (asm_simp_tac (simpset() addsimps [preal_mult_commute,preal_add_commute]) 1);
by (auto_tac (claset(),simpset() addsimps [real_mult_congruent2_lemma]));
qed "real_mult_congruent2";
Goalw [real_mult_def]
"Abs_real((realrel^^{(x1,y1)})) * Abs_real((realrel^^{(x2,y2)})) = \
\ Abs_real(realrel ^^ {(x1*x2+y1*y2,x1*y2+x2*y1)})";
by (simp_tac (simpset() addsimps
[[equiv_realrel, real_mult_congruent2] MRS UN_equiv_class2]) 1);
qed "real_mult";
Goal "(z::real) * w = w * z";
by (res_inst_tac [("z","z")] eq_Abs_real 1);
by (res_inst_tac [("z","w")] eq_Abs_real 1);
by (asm_simp_tac
(simpset() addsimps [real_mult] @ preal_add_ac @ preal_mult_ac) 1);
qed "real_mult_commute";
Goal "((z1::real) * z2) * z3 = z1 * (z2 * z3)";
by (res_inst_tac [("z","z1")] eq_Abs_real 1);
by (res_inst_tac [("z","z2")] eq_Abs_real 1);
by (res_inst_tac [("z","z3")] eq_Abs_real 1);
by (asm_simp_tac (simpset() addsimps [preal_add_mult_distrib2,real_mult] @
preal_add_ac @ preal_mult_ac) 1);
qed "real_mult_assoc";
Goal "(z1::real) * (z2 * z3) = z2 * (z1 * z3)";
by (rtac (real_mult_commute RS trans) 1);
by (rtac (real_mult_assoc RS trans) 1);
by (rtac (real_mult_commute RS arg_cong) 1);
qed "real_mult_left_commute";
(* real multiplication is an AC operator *)
bind_thms ("real_mult_ac",
[real_mult_assoc, real_mult_commute, real_mult_left_commute]);
Goalw [real_one_def,pnat_one_def] "1r * z = z";
by (res_inst_tac [("z","z")] eq_Abs_real 1);
by (asm_full_simp_tac
(simpset() addsimps [real_mult,
preal_add_mult_distrib2,preal_mult_1_right]
@ preal_mult_ac @ preal_add_ac) 1);
qed "real_mult_1";
Addsimps [real_mult_1];
Goal "z * 1r = z";
by (simp_tac (simpset() addsimps [real_mult_commute]) 1);
qed "real_mult_1_right";
Addsimps [real_mult_1_right];
Goalw [real_zero_def,pnat_one_def] "0 * z = (0::real)";
by (res_inst_tac [("z","z")] eq_Abs_real 1);
by (asm_full_simp_tac (simpset() addsimps [real_mult,
preal_add_mult_distrib2,preal_mult_1_right]
@ preal_mult_ac @ preal_add_ac) 1);
qed "real_mult_0";
Goal "z * 0 = (0::real)";
by (simp_tac (simpset() addsimps [real_mult_commute, real_mult_0]) 1);
qed "real_mult_0_right";
Addsimps [real_mult_0_right, real_mult_0];
Goal "-(x * y) = (-x) * (y::real)";
by (res_inst_tac [("z","x")] eq_Abs_real 1);
by (res_inst_tac [("z","y")] eq_Abs_real 1);
by (auto_tac (claset(),
simpset() addsimps [real_minus,real_mult]
@ preal_mult_ac @ preal_add_ac));
qed "real_minus_mult_eq1";
Goal "-(x * y) = x * (- y :: real)";
by (simp_tac (simpset() addsimps [inst "z" "x" real_mult_commute,
real_minus_mult_eq1]) 1);
qed "real_minus_mult_eq2";
Addsimps [real_minus_mult_eq1 RS sym, real_minus_mult_eq2 RS sym];
Goal "(- 1r) * z = -z";
by (Simp_tac 1);
qed "real_mult_minus_1";
Goal "z * (- 1r) = -z";
by (stac real_mult_commute 1);
by (Simp_tac 1);
qed "real_mult_minus_1_right";
Addsimps [real_mult_minus_1_right];
Goal "(-x) * (-y) = x * (y::real)";
by (full_simp_tac (simpset() addsimps [real_minus_mult_eq2 RS sym,
real_minus_mult_eq1 RS sym]) 1);
qed "real_minus_mult_cancel";
Addsimps [real_minus_mult_cancel];
Goal "(-x) * y = x * (- y :: real)";
by (full_simp_tac (simpset() addsimps [real_minus_mult_eq2 RS sym,
real_minus_mult_eq1 RS sym]) 1);
qed "real_minus_mult_commute";
(** Lemmas **)
Goal "(z::real) + v = z' + v' ==> z + (v + w) = z' + (v' + w)";
by (asm_simp_tac (simpset() addsimps [real_add_assoc RS sym]) 1);
qed "real_add_assoc_cong";
Goal "(z::real) + (v + w) = v + (z + w)";
by (REPEAT (ares_tac [real_add_commute RS real_add_assoc_cong] 1));
qed "real_add_assoc_swap";
Goal "((z1::real) + z2) * w = (z1 * w) + (z2 * w)";
by (res_inst_tac [("z","z1")] eq_Abs_real 1);
by (res_inst_tac [("z","z2")] eq_Abs_real 1);
by (res_inst_tac [("z","w")] eq_Abs_real 1);
by (asm_simp_tac
(simpset() addsimps [preal_add_mult_distrib2, real_add, real_mult] @
preal_add_ac @ preal_mult_ac) 1);
qed "real_add_mult_distrib";
val real_mult_commute'= inst "z" "w" real_mult_commute;
Goal "(w::real) * (z1 + z2) = (w * z1) + (w * z2)";
by (simp_tac (simpset() addsimps [real_mult_commute',
real_add_mult_distrib]) 1);
qed "real_add_mult_distrib2";
Goalw [real_diff_def] "((z1::real) - z2) * w = (z1 * w) - (z2 * w)";
by (simp_tac (simpset() addsimps [real_add_mult_distrib]) 1);
qed "real_diff_mult_distrib";
Goal "(w::real) * (z1 - z2) = (w * z1) - (w * z2)";
by (simp_tac (simpset() addsimps [real_mult_commute',
real_diff_mult_distrib]) 1);
qed "real_diff_mult_distrib2";
(*** one and zero are distinct ***)
Goalw [real_zero_def,real_one_def] "0 ~= 1r";
by (auto_tac (claset(),
simpset() addsimps [preal_self_less_add_left RS preal_not_refl2]));
qed "real_zero_not_eq_one";
(*** existence of inverse ***)
(** lemma -- alternative definition of 0 **)
Goalw [real_zero_def] "0 = Abs_real (realrel ^^ {(x, x)})";
by (auto_tac (claset(),simpset() addsimps [preal_add_commute]));
qed "real_zero_iff";
Goalw [real_zero_def,real_one_def]
"!!(x::real). x ~= 0 ==> EX y. x*y = 1r";
by (res_inst_tac [("z","x")] eq_Abs_real 1);
by (cut_inst_tac [("r1.0","xa"),("r2.0","y")] preal_linear 1);
by (auto_tac (claset() addSDs [preal_less_add_left_Ex],
simpset() addsimps [real_zero_iff RS sym]));
by (res_inst_tac [("x","Abs_real (realrel ^^ \
\ {(preal_of_prat(prat_of_pnat 1p),pinv(D)+\
\ preal_of_prat(prat_of_pnat 1p))})")] exI 1);
by (res_inst_tac [("x","Abs_real (realrel ^^ \
\ {(pinv(D)+preal_of_prat(prat_of_pnat 1p),\
\ preal_of_prat(prat_of_pnat 1p))})")] exI 2);
by (auto_tac (claset(),
simpset() addsimps [real_mult,
pnat_one_def,preal_mult_1_right,preal_add_mult_distrib2,
preal_add_mult_distrib,preal_mult_1,preal_mult_inv_right]
@ preal_add_ac @ preal_mult_ac));
qed "real_mult_inv_right_ex";
Goal "x ~= 0 ==> EX y. y*x = 1r";
by (dtac real_mult_inv_right_ex 1);
by (auto_tac (claset(), simpset() addsimps [real_mult_commute]));
qed "real_mult_inv_left_ex";
Goalw [real_inverse_def] "x ~= 0 ==> inverse(x)*x = 1r";
by (ftac real_mult_inv_left_ex 1);
by (Step_tac 1);
by (rtac someI2 1);
by Auto_tac;
qed "real_mult_inv_left";
Addsimps [real_mult_inv_left];
Goal "x ~= 0 ==> x*inverse(x) = 1r";
by (stac real_mult_commute 1);
by (auto_tac (claset(), simpset() addsimps [real_mult_inv_left]));
qed "real_mult_inv_right";
Addsimps [real_mult_inv_right];
(** Inverse of zero! Useful to simplify certain equations **)
Goalw [real_inverse_def] "inverse 0 = (0::real)";
by (rtac someI2 1);
by (auto_tac (claset(), simpset() addsimps [real_zero_not_eq_one]));
qed "INVERSE_ZERO";
Goal "a / (0::real) = 0";
by (simp_tac (simpset() addsimps [real_divide_def, INVERSE_ZERO]) 1);
qed "DIVISION_BY_ZERO"; (*NOT for adding to default simpset*)
fun real_div_undefined_case_tac s i =
case_tac s i THEN
asm_simp_tac (simpset() addsimps [DIVISION_BY_ZERO, INVERSE_ZERO]) i;
Goal "(c::real) ~= 0 ==> (c*a=c*b) = (a=b)";
by Auto_tac;
by (dres_inst_tac [("f","%x. x*inverse c")] arg_cong 1);
by (asm_full_simp_tac (simpset() addsimps real_mult_ac) 1);
qed "real_mult_left_cancel";
Goal "(c::real) ~= 0 ==> (a*c=b*c) = (a=b)";
by (Step_tac 1);
by (dres_inst_tac [("f","%x. x*inverse c")] arg_cong 1);
by (asm_full_simp_tac (simpset() addsimps real_mult_ac) 1);
qed "real_mult_right_cancel";
Goal "c*a ~= c*b ==> a ~= b";
by Auto_tac;
qed "real_mult_left_cancel_ccontr";
Goal "a*c ~= b*c ==> a ~= b";
by Auto_tac;
qed "real_mult_right_cancel_ccontr";
Goalw [real_inverse_def] "x ~= 0 ==> inverse(x::real) ~= 0";
by (ftac real_mult_inv_left_ex 1);
by (etac exE 1);
by (rtac someI2 1);
by (auto_tac (claset(),
simpset() addsimps [real_mult_0, real_zero_not_eq_one]));
qed "real_inverse_not_zero";
Goal "[| x ~= 0; y ~= 0 |] ==> x * y ~= (0::real)";
by (Step_tac 1);
by (dres_inst_tac [("f","%z. inverse x*z")] arg_cong 1);
by (asm_full_simp_tac (simpset() addsimps [real_mult_assoc RS sym]) 1);
qed "real_mult_not_zero";
bind_thm ("real_mult_not_zeroE",real_mult_not_zero RS notE);
Goal "inverse(inverse (x::real)) = x";
by (real_div_undefined_case_tac "x=0" 1);
by (res_inst_tac [("c1","inverse x")] (real_mult_right_cancel RS iffD1) 1);
by (etac real_inverse_not_zero 1);
by (auto_tac (claset() addDs [real_inverse_not_zero],simpset()));
qed "real_inverse_inverse";
Addsimps [real_inverse_inverse];
Goalw [real_inverse_def] "inverse(1r) = 1r";
by (cut_facts_tac [real_zero_not_eq_one RS
not_sym RS real_mult_inv_left_ex] 1);
by (auto_tac (claset(),
simpset() addsimps [real_zero_not_eq_one RS not_sym]));
qed "real_inverse_1";
Addsimps [real_inverse_1];
Goal "inverse(-x) = -inverse(x::real)";
by (real_div_undefined_case_tac "x=0" 1);
by (res_inst_tac [("c1","-x")] (real_mult_right_cancel RS iffD1) 1);
by (stac real_mult_inv_left 2);
by Auto_tac;
qed "real_minus_inverse";
Goal "inverse(x*y) = inverse(x)*inverse(y::real)";
by (real_div_undefined_case_tac "x=0" 1);
by (real_div_undefined_case_tac "y=0" 1);
by (forw_inst_tac [("y","y")] real_mult_not_zero 1 THEN assume_tac 1);
by (res_inst_tac [("c1","x")] (real_mult_left_cancel RS iffD1) 1);
by (auto_tac (claset(),simpset() addsimps [real_mult_assoc RS sym]));
by (res_inst_tac [("c1","y")] (real_mult_left_cancel RS iffD1) 1);
by (auto_tac (claset(),simpset() addsimps [real_mult_left_commute]));
by (asm_simp_tac (simpset() addsimps [real_mult_assoc RS sym]) 1);
qed "real_inverse_distrib";
Goal "(x::real) * (y/z) = (x*y)/z";
by (simp_tac (simpset() addsimps [real_divide_def, real_mult_assoc]) 1);
qed "real_times_divide1_eq";
Goal "(y/z) * (x::real) = (y*x)/z";
by (simp_tac (simpset() addsimps [real_divide_def]@real_mult_ac) 1);
qed "real_times_divide2_eq";
Addsimps [real_times_divide1_eq, real_times_divide2_eq];
Goal "(x::real) / (y/z) = (x*z)/y";
by (simp_tac (simpset() addsimps [real_divide_def, real_inverse_distrib]@
real_mult_ac) 1);
qed "real_divide_divide1_eq";
Goal "((x::real) / y) / z = x/(y*z)";
by (simp_tac (simpset() addsimps [real_divide_def, real_inverse_distrib,
real_mult_assoc]) 1);
qed "real_divide_divide2_eq";
Addsimps [real_divide_divide1_eq, real_divide_divide2_eq];
(** As with multiplication, pull minus signs OUT of the / operator **)
Goal "(-x) / (y::real) = - (x/y)";
by (simp_tac (simpset() addsimps [real_divide_def]) 1);
qed "real_minus_divide_eq";
Addsimps [real_minus_divide_eq];
Goal "(x / -(y::real)) = - (x/y)";
by (simp_tac (simpset() addsimps [real_divide_def, real_minus_inverse]) 1);
qed "real_divide_minus_eq";
Addsimps [real_divide_minus_eq];
Goal "(x+y)/(z::real) = x/z + y/z";
by (simp_tac (simpset() addsimps [real_divide_def, real_add_mult_distrib]) 1);
qed "real_add_divide_distrib";
(*The following would e.g. convert (x+y)/2 to x/2 + y/2. Sometimes that
leads to cancellations in x or y, but is also prevents "multiplying out"
the 2 in e.g. (x+y)/2 = 5.
Addsimps [inst "z" "number_of ?w" real_add_divide_distrib];
**)
(*---------------------------------------------------------
Theorems for ordering
--------------------------------------------------------*)
(* prove introduction and elimination rules for real_less *)
(* real_less is a strong order i.e. nonreflexive and transitive *)
(*** lemmas ***)
Goal "!!(x::preal). [| x = y; x1 = y1 |] ==> x + y1 = x1 + y";
by (asm_simp_tac (simpset() addsimps [preal_add_commute]) 1);
qed "preal_lemma_eq_rev_sum";
Goal "!!(b::preal). x + (b + y) = x1 + (b + y1) ==> x + y = x1 + y1";
by (asm_full_simp_tac (simpset() addsimps preal_add_ac) 1);
qed "preal_add_left_commute_cancel";
Goal "!!(x::preal). [| x + y2a = x2a + y; \
\ x + y2b = x2b + y |] \
\ ==> x2a + y2b = x2b + y2a";
by (dtac preal_lemma_eq_rev_sum 1);
by (assume_tac 1);
by (thin_tac "x + y2b = x2b + y" 1);
by (asm_full_simp_tac (simpset() addsimps preal_add_ac) 1);
by (dtac preal_add_left_commute_cancel 1);
by (asm_full_simp_tac (simpset() addsimps preal_add_ac) 1);
qed "preal_lemma_for_not_refl";
Goal "~ (R::real) < R";
by (res_inst_tac [("z","R")] eq_Abs_real 1);
by (auto_tac (claset(),simpset() addsimps [real_less_def]));
by (dtac preal_lemma_for_not_refl 1);
by (assume_tac 1 THEN rotate_tac 2 1);
by (auto_tac (claset(),simpset() addsimps [preal_less_not_refl]));
qed "real_less_not_refl";
(*** y < y ==> P ***)
bind_thm("real_less_irrefl", real_less_not_refl RS notE);
AddSEs [real_less_irrefl];
Goal "!!(x::real). x < y ==> x ~= y";
by (auto_tac (claset(),simpset() addsimps [real_less_not_refl]));
qed "real_not_refl2";
(* lemma re-arranging and eliminating terms *)
Goal "!! (a::preal). [| a + b = c + d; \
\ x2b + d + (c + y2e) < a + y2b + (x2e + b) |] \
\ ==> x2b + y2e < x2e + y2b";
by (asm_full_simp_tac (simpset() addsimps preal_add_ac) 1);
by (res_inst_tac [("C","c+d")] preal_add_left_less_cancel 1);
by (asm_full_simp_tac (simpset() addsimps [preal_add_assoc RS sym]) 1);
qed "preal_lemma_trans";
(** heavy re-writing involved*)
Goal "!!(R1::real). [| R1 < R2; R2 < R3 |] ==> R1 < R3";
by (res_inst_tac [("z","R1")] eq_Abs_real 1);
by (res_inst_tac [("z","R2")] eq_Abs_real 1);
by (res_inst_tac [("z","R3")] eq_Abs_real 1);
by (auto_tac (claset(),simpset() addsimps [real_less_def]));
by (REPEAT(rtac exI 1));
by (EVERY[rtac conjI 1, rtac conjI 2]);
by (REPEAT(Blast_tac 2));
by (dtac preal_lemma_for_not_refl 1 THEN assume_tac 1);
by (blast_tac (claset() addDs [preal_add_less_mono]
addIs [preal_lemma_trans]) 1);
qed "real_less_trans";
Goal "!! (R1::real). R1 < R2 ==> ~ (R2 < R1)";
by (rtac notI 1);
by (dtac real_less_trans 1 THEN assume_tac 1);
by (asm_full_simp_tac (simpset() addsimps [real_less_not_refl]) 1);
qed "real_less_not_sym";
(* [| x < y; ~P ==> y < x |] ==> P *)
bind_thm ("real_less_asym", real_less_not_sym RS contrapos_np);
Goalw [real_of_preal_def]
"real_of_preal ((z1::preal) + z2) = \
\ real_of_preal z1 + real_of_preal z2";
by (asm_simp_tac (simpset() addsimps [real_add,
preal_add_mult_distrib,preal_mult_1] addsimps preal_add_ac) 1);
qed "real_of_preal_add";
Goalw [real_of_preal_def]
"real_of_preal ((z1::preal) * z2) = \
\ real_of_preal z1* real_of_preal z2";
by (full_simp_tac (simpset() addsimps [real_mult,
preal_add_mult_distrib2,preal_mult_1,
preal_mult_1_right,pnat_one_def]
@ preal_add_ac @ preal_mult_ac) 1);
qed "real_of_preal_mult";
Goalw [real_of_preal_def]
"!!(x::preal). y < x ==> \
\ EX m. Abs_real (realrel ^^ {(x,y)}) = real_of_preal m";
by (auto_tac (claset() addSDs [preal_less_add_left_Ex],
simpset() addsimps preal_add_ac));
qed "real_of_preal_ExI";
Goalw [real_of_preal_def]
"!!(x::preal). EX m. Abs_real (realrel ^^ {(x,y)}) = \
\ real_of_preal m ==> y < x";
by (auto_tac (claset(),
simpset() addsimps
[preal_add_commute,preal_add_assoc]));
by (asm_full_simp_tac (simpset() addsimps
[preal_add_assoc RS sym,preal_self_less_add_left]) 1);
qed "real_of_preal_ExD";
Goal "(EX m. Abs_real (realrel ^^ {(x,y)}) = real_of_preal m) = (y < x)";
by (blast_tac (claset() addSIs [real_of_preal_ExI,real_of_preal_ExD]) 1);
qed "real_of_preal_iff";
(*** Gleason prop 9-4.4 p 127 ***)
Goalw [real_of_preal_def,real_zero_def]
"EX m. (x::real) = real_of_preal m | x = 0 | x = -(real_of_preal m)";
by (res_inst_tac [("z","x")] eq_Abs_real 1);
by (auto_tac (claset(),simpset() addsimps [real_minus] @ preal_add_ac));
by (cut_inst_tac [("r1.0","x"),("r2.0","y")] preal_linear 1);
by (auto_tac (claset() addSDs [preal_less_add_left_Ex],
simpset() addsimps [preal_add_assoc RS sym]));
by (auto_tac (claset(),simpset() addsimps [preal_add_commute]));
qed "real_of_preal_trichotomy";
Goal "!!P. [| !!m. x = real_of_preal m ==> P; \
\ x = 0 ==> P; \
\ !!m. x = -(real_of_preal m) ==> P |] ==> P";
by (cut_inst_tac [("x","x")] real_of_preal_trichotomy 1);
by Auto_tac;
qed "real_of_preal_trichotomyE";
Goalw [real_of_preal_def]
"real_of_preal m1 < real_of_preal m2 ==> m1 < m2";
by (auto_tac (claset(),simpset() addsimps [real_less_def] @ preal_add_ac));
by (auto_tac (claset(),simpset() addsimps [preal_add_assoc RS sym]));
by (auto_tac (claset(),simpset() addsimps preal_add_ac));
qed "real_of_preal_lessD";
Goal "m1 < m2 ==> real_of_preal m1 < real_of_preal m2";
by (dtac preal_less_add_left_Ex 1);
by (auto_tac (claset(),
simpset() addsimps [real_of_preal_add,
real_of_preal_def,real_less_def]));
by (REPEAT(rtac exI 1));
by (EVERY[rtac conjI 1, rtac conjI 2]);
by (REPEAT(Blast_tac 2));
by (simp_tac (simpset() addsimps [preal_self_less_add_left]
delsimps [preal_add_less_iff2]) 1);
qed "real_of_preal_lessI";
Goal "(real_of_preal m1 < real_of_preal m2) = (m1 < m2)";
by (blast_tac (claset() addIs [real_of_preal_lessI,real_of_preal_lessD]) 1);
qed "real_of_preal_less_iff1";
Addsimps [real_of_preal_less_iff1];
Goal "- real_of_preal m < real_of_preal m";
by (auto_tac (claset(),
simpset() addsimps
[real_of_preal_def,real_less_def,real_minus]));
by (REPEAT(rtac exI 1));
by (EVERY[rtac conjI 1, rtac conjI 2]);
by (REPEAT(Blast_tac 2));
by (full_simp_tac (simpset() addsimps preal_add_ac) 1);
by (full_simp_tac (simpset() addsimps [preal_self_less_add_right,
preal_add_assoc RS sym]) 1);
qed "real_of_preal_minus_less_self";
Goalw [real_zero_def] "- real_of_preal m < 0";
by (auto_tac (claset(),
simpset() addsimps [real_of_preal_def,
real_less_def,real_minus]));
by (REPEAT(rtac exI 1));
by (EVERY[rtac conjI 1, rtac conjI 2]);
by (REPEAT(Blast_tac 2));
by (full_simp_tac (simpset() addsimps
[preal_self_less_add_right] @ preal_add_ac) 1);
qed "real_of_preal_minus_less_zero";
Goal "~ 0 < - real_of_preal m";
by (cut_facts_tac [real_of_preal_minus_less_zero] 1);
by (fast_tac (claset() addDs [real_less_trans]
addEs [real_less_irrefl]) 1);
qed "real_of_preal_not_minus_gt_zero";
Goalw [real_zero_def] "0 < real_of_preal m";
by (auto_tac (claset(),simpset() addsimps
[real_of_preal_def,real_less_def,real_minus]));
by (REPEAT(rtac exI 1));
by (EVERY[rtac conjI 1, rtac conjI 2]);
by (REPEAT(Blast_tac 2));
by (full_simp_tac (simpset() addsimps
[preal_self_less_add_right] @ preal_add_ac) 1);
qed "real_of_preal_zero_less";
Goal "~ real_of_preal m < 0";
by (cut_facts_tac [real_of_preal_zero_less] 1);
by (blast_tac (claset() addDs [real_less_trans]
addEs [real_less_irrefl]) 1);
qed "real_of_preal_not_less_zero";
Goal "0 < - (- real_of_preal m)";
by (simp_tac (simpset() addsimps
[real_of_preal_zero_less]) 1);
qed "real_minus_minus_zero_less";
(* another lemma *)
Goalw [real_zero_def]
"0 < real_of_preal m + real_of_preal m1";
by (auto_tac (claset(),
simpset() addsimps [real_of_preal_def,
real_less_def,real_add]));
by (REPEAT(rtac exI 1));
by (EVERY[rtac conjI 1, rtac conjI 2]);
by (REPEAT(Blast_tac 2));
by (full_simp_tac (simpset() addsimps preal_add_ac) 1);
by (full_simp_tac (simpset() addsimps [preal_self_less_add_right,
preal_add_assoc RS sym]) 1);
qed "real_of_preal_sum_zero_less";
Goal "- real_of_preal m < real_of_preal m1";
by (auto_tac (claset(),
simpset() addsimps [real_of_preal_def,
real_less_def,real_minus]));
by (REPEAT(rtac exI 1));
by (EVERY[rtac conjI 1, rtac conjI 2]);
by (REPEAT(Blast_tac 2));
by (full_simp_tac (simpset() addsimps preal_add_ac) 1);
by (full_simp_tac (simpset() addsimps [preal_self_less_add_right,
preal_add_assoc RS sym]) 1);
qed "real_of_preal_minus_less_all";
Goal "~ real_of_preal m < - real_of_preal m1";
by (cut_facts_tac [real_of_preal_minus_less_all] 1);
by (blast_tac (claset() addDs [real_less_trans]
addEs [real_less_irrefl]) 1);
qed "real_of_preal_not_minus_gt_all";
Goal "- real_of_preal m1 < - real_of_preal m2 \
\ ==> real_of_preal m2 < real_of_preal m1";
by (auto_tac (claset(),
simpset() addsimps [real_of_preal_def,
real_less_def,real_minus]));
by (REPEAT(rtac exI 1));
by (EVERY[rtac conjI 1, rtac conjI 2]);
by (REPEAT(Blast_tac 2));
by (auto_tac (claset(),simpset() addsimps preal_add_ac));
by (asm_full_simp_tac (simpset() addsimps [preal_add_assoc RS sym]) 1);
by (auto_tac (claset(),simpset() addsimps preal_add_ac));
qed "real_of_preal_minus_less_rev1";
Goal "real_of_preal m1 < real_of_preal m2 \
\ ==> - real_of_preal m2 < - real_of_preal m1";
by (auto_tac (claset(),
simpset() addsimps [real_of_preal_def,
real_less_def,real_minus]));
by (REPEAT(rtac exI 1));
by (EVERY[rtac conjI 1, rtac conjI 2]);
by (REPEAT(Blast_tac 2));
by (auto_tac (claset(),simpset() addsimps preal_add_ac));
by (asm_full_simp_tac (simpset() addsimps [preal_add_assoc RS sym]) 1);
by (auto_tac (claset(),simpset() addsimps preal_add_ac));
qed "real_of_preal_minus_less_rev2";
Goal "(- real_of_preal m1 < - real_of_preal m2) = \
\ (real_of_preal m2 < real_of_preal m1)";
by (blast_tac (claset() addSIs [real_of_preal_minus_less_rev1,
real_of_preal_minus_less_rev2]) 1);
qed "real_of_preal_minus_less_rev_iff";
Addsimps [real_of_preal_minus_less_rev_iff];
(*** linearity ***)
Goal "(R1::real) < R2 | R1 = R2 | R2 < R1";
by (res_inst_tac [("x","R1")] real_of_preal_trichotomyE 1);
by (ALLGOALS(res_inst_tac [("x","R2")] real_of_preal_trichotomyE));
by (auto_tac (claset() addSDs [preal_le_anti_sym],
simpset() addsimps [preal_less_le_iff,real_of_preal_minus_less_zero,
real_of_preal_zero_less,real_of_preal_minus_less_all]));
qed "real_linear";
Goal "!!w::real. (w ~= z) = (w<z | z<w)";
by (cut_facts_tac [real_linear] 1);
by (Blast_tac 1);
qed "real_neq_iff";
Goal "!!(R1::real). [| R1 < R2 ==> P; R1 = R2 ==> P; \
\ R2 < R1 ==> P |] ==> P";
by (cut_inst_tac [("R1.0","R1"),("R2.0","R2")] real_linear 1);
by Auto_tac;
qed "real_linear_less2";
(*** Properties of <= ***)
Goalw [real_le_def] "~(w < z) ==> z <= (w::real)";
by (assume_tac 1);
qed "real_leI";
Goalw [real_le_def] "z<=w ==> ~(w<(z::real))";
by (assume_tac 1);
qed "real_leD";
bind_thm ("real_leE", make_elim real_leD);
Goal "(~(w < z)) = (z <= (w::real))";
by (blast_tac (claset() addSIs [real_leI,real_leD]) 1);
qed "real_less_le_iff";
Goalw [real_le_def] "~ z <= w ==> w<(z::real)";
by (Blast_tac 1);
qed "not_real_leE";
Goalw [real_le_def] "z < w ==> z <= (w::real)";
by (blast_tac (claset() addEs [real_less_asym]) 1);
qed "real_less_imp_le";
Goalw [real_le_def] "!!(x::real). x <= y ==> x < y | x = y";
by (cut_facts_tac [real_linear] 1);
by (blast_tac (claset() addEs [real_less_irrefl,real_less_asym]) 1);
qed "real_le_imp_less_or_eq";
Goalw [real_le_def] "z<w | z=w ==> z <=(w::real)";
by (cut_facts_tac [real_linear] 1);
by (fast_tac (claset() addEs [real_less_irrefl,real_less_asym]) 1);
qed "real_less_or_eq_imp_le";
Goal "(x <= (y::real)) = (x < y | x=y)";
by (REPEAT(ares_tac [iffI, real_less_or_eq_imp_le, real_le_imp_less_or_eq] 1));
qed "real_le_less";
Goal "w <= (w::real)";
by (simp_tac (simpset() addsimps [real_le_less]) 1);
qed "real_le_refl";
AddIffs [real_le_refl];
(* Axiom 'linorder_linear' of class 'linorder': *)
Goal "(z::real) <= w | w <= z";
by (simp_tac (simpset() addsimps [real_le_less]) 1);
by (cut_facts_tac [real_linear] 1);
by (Blast_tac 1);
qed "real_le_linear";
Goal "[| i <= j; j < k |] ==> i < (k::real)";
by (dtac real_le_imp_less_or_eq 1);
by (blast_tac (claset() addIs [real_less_trans]) 1);
qed "real_le_less_trans";
Goal "!! (i::real). [| i < j; j <= k |] ==> i < k";
by (dtac real_le_imp_less_or_eq 1);
by (blast_tac (claset() addIs [real_less_trans]) 1);
qed "real_less_le_trans";
Goal "[| i <= j; j <= k |] ==> i <= (k::real)";
by (EVERY1 [dtac real_le_imp_less_or_eq, dtac real_le_imp_less_or_eq,
rtac real_less_or_eq_imp_le, blast_tac (claset() addIs [real_less_trans])]);
qed "real_le_trans";
Goal "[| z <= w; w <= z |] ==> z = (w::real)";
by (EVERY1 [dtac real_le_imp_less_or_eq, dtac real_le_imp_less_or_eq,
fast_tac (claset() addEs [real_less_irrefl,real_less_asym])]);
qed "real_le_anti_sym";
Goal "[| ~ y < x; y ~= x |] ==> x < (y::real)";
by (rtac not_real_leE 1);
by (blast_tac (claset() addDs [real_le_imp_less_or_eq]) 1);
qed "not_less_not_eq_real_less";
(* Axiom 'order_less_le' of class 'order': *)
Goal "(w::real) < z = (w <= z & w ~= z)";
by (simp_tac (simpset() addsimps [real_le_def, real_neq_iff]) 1);
by (blast_tac (claset() addSEs [real_less_asym]) 1);
qed "real_less_le";
Goal "(0 < -R) = (R < (0::real))";
by (res_inst_tac [("x","R")] real_of_preal_trichotomyE 1);
by (auto_tac (claset(),
simpset() addsimps [real_of_preal_not_minus_gt_zero,
real_of_preal_not_less_zero,real_of_preal_zero_less,
real_of_preal_minus_less_zero]));
qed "real_minus_zero_less_iff";
Addsimps [real_minus_zero_less_iff];
Goal "(-R < 0) = ((0::real) < R)";
by (res_inst_tac [("x","R")] real_of_preal_trichotomyE 1);
by (auto_tac (claset(),
simpset() addsimps [real_of_preal_not_minus_gt_zero,
real_of_preal_not_less_zero,real_of_preal_zero_less,
real_of_preal_minus_less_zero]));
qed "real_minus_zero_less_iff2";
(*Alternative definition for real_less*)
Goal "R < S ==> EX T::real. 0 < T & R + T = S";
by (res_inst_tac [("x","R")] real_of_preal_trichotomyE 1);
by (ALLGOALS(res_inst_tac [("x","S")] real_of_preal_trichotomyE));
by (auto_tac (claset() addSDs [preal_less_add_left_Ex],
simpset() addsimps [real_of_preal_not_minus_gt_all,
real_of_preal_add, real_of_preal_not_less_zero,
real_less_not_refl,
real_of_preal_not_minus_gt_zero]));
by (res_inst_tac [("x","real_of_preal D")] exI 1);
by (res_inst_tac [("x","real_of_preal m+real_of_preal ma")] exI 2);
by (res_inst_tac [("x","real_of_preal m")] exI 3);
by (res_inst_tac [("x","real_of_preal D")] exI 4);
by (auto_tac (claset(),
simpset() addsimps [real_of_preal_zero_less,
real_of_preal_sum_zero_less,real_add_assoc]));
qed "real_less_add_positive_left_Ex";
(** change naff name(s)! **)
Goal "(W < S) ==> (0 < S + (-W::real))";
by (dtac real_less_add_positive_left_Ex 1);
by (auto_tac (claset(),
simpset() addsimps [real_add_minus,
real_add_zero_right] @ real_add_ac));
qed "real_less_sum_gt_zero";
Goal "!!S::real. T = S + W ==> S = T + (-W)";
by (asm_simp_tac (simpset() addsimps real_add_ac) 1);
qed "real_lemma_change_eq_subj";
(* FIXME: long! *)
Goal "(0 < S + (-W::real)) ==> (W < S)";
by (rtac ccontr 1);
by (dtac (real_leI RS real_le_imp_less_or_eq) 1);
by (auto_tac (claset(),
simpset() addsimps [real_less_not_refl]));
by (EVERY1[dtac real_less_add_positive_left_Ex, etac exE, etac conjE]);
by (Asm_full_simp_tac 1);
by (dtac real_lemma_change_eq_subj 1);
by Auto_tac;
by (dtac real_less_sum_gt_zero 1);
by (asm_full_simp_tac (simpset() addsimps real_add_ac) 1);
by (EVERY1[rotate_tac 1, dtac (real_add_left_commute RS ssubst)]);
by (auto_tac (claset() addEs [real_less_asym], simpset()));
qed "real_sum_gt_zero_less";
Goal "(0 < S + (-W::real)) = (W < S)";
by (blast_tac (claset() addIs [real_less_sum_gt_zero,
real_sum_gt_zero_less]) 1);
qed "real_less_sum_gt_0_iff";
Goalw [real_diff_def] "(x<y) = (x-y < (0::real))";
by (stac (real_minus_zero_less_iff RS sym) 1);
by (simp_tac (simpset() addsimps [real_add_commute,
real_less_sum_gt_0_iff]) 1);
qed "real_less_eq_diff";
(*** Subtraction laws ***)
Goal "x + (y - z) = (x + y) - (z::real)";
by (simp_tac (simpset() addsimps real_diff_def::real_add_ac) 1);
qed "real_add_diff_eq";
Goal "(x - y) + z = (x + z) - (y::real)";
by (simp_tac (simpset() addsimps real_diff_def::real_add_ac) 1);
qed "real_diff_add_eq";
Goal "(x - y) - z = x - (y + (z::real))";
by (simp_tac (simpset() addsimps real_diff_def::real_add_ac) 1);
qed "real_diff_diff_eq";
Goal "x - (y - z) = (x + z) - (y::real)";
by (simp_tac (simpset() addsimps real_diff_def::real_add_ac) 1);
qed "real_diff_diff_eq2";
Goal "(x-y < z) = (x < z + (y::real))";
by (stac real_less_eq_diff 1);
by (res_inst_tac [("y1", "z")] (real_less_eq_diff RS ssubst) 1);
by (simp_tac (simpset() addsimps real_diff_def::real_add_ac) 1);
qed "real_diff_less_eq";
Goal "(x < z-y) = (x + (y::real) < z)";
by (stac real_less_eq_diff 1);
by (res_inst_tac [("y1", "z-y")] (real_less_eq_diff RS ssubst) 1);
by (simp_tac (simpset() addsimps real_diff_def::real_add_ac) 1);
qed "real_less_diff_eq";
Goalw [real_le_def] "(x-y <= z) = (x <= z + (y::real))";
by (simp_tac (simpset() addsimps [real_less_diff_eq]) 1);
qed "real_diff_le_eq";
Goalw [real_le_def] "(x <= z-y) = (x + (y::real) <= z)";
by (simp_tac (simpset() addsimps [real_diff_less_eq]) 1);
qed "real_le_diff_eq";
Goalw [real_diff_def] "(x-y = z) = (x = z + (y::real))";
by (auto_tac (claset(), simpset() addsimps [real_add_assoc]));
qed "real_diff_eq_eq";
Goalw [real_diff_def] "(x = z-y) = (x + (y::real) = z)";
by (auto_tac (claset(), simpset() addsimps [real_add_assoc]));
qed "real_eq_diff_eq";
(*This list of rewrites simplifies (in)equalities by bringing subtractions
to the top and then moving negative terms to the other side.
Use with real_add_ac*)
bind_thms ("real_compare_rls",
[symmetric real_diff_def,
real_add_diff_eq, real_diff_add_eq, real_diff_diff_eq, real_diff_diff_eq2,
real_diff_less_eq, real_less_diff_eq, real_diff_le_eq, real_le_diff_eq,
real_diff_eq_eq, real_eq_diff_eq]);
(** For the cancellation simproc.
The idea is to cancel like terms on opposite sides by subtraction **)
Goal "(x::real) - y = x' - y' ==> (x<y) = (x'<y')";
by (stac real_less_eq_diff 1);
by (res_inst_tac [("y1", "y")] (real_less_eq_diff RS ssubst) 1);
by (Asm_simp_tac 1);
qed "real_less_eqI";
Goal "(x::real) - y = x' - y' ==> (y<=x) = (y'<=x')";
by (dtac real_less_eqI 1);
by (asm_simp_tac (simpset() addsimps [real_le_def]) 1);
qed "real_le_eqI";
Goal "(x::real) - y = x' - y' ==> (x=y) = (x'=y')";
by Safe_tac;
by (ALLGOALS
(asm_full_simp_tac
(simpset() addsimps [real_eq_diff_eq, real_diff_eq_eq])));
qed "real_eq_eqI";