src/HOL/Real/RealDef.thy
author paulson
Fri Apr 23 11:04:07 2004 +0200 (2004-04-23)
changeset 14658 b1293d0f8d5f
parent 14497 76cdbeb0c9de
child 14691 e1eedc8cad37
permissions -rw-r--r--
congruent2 now allows different equiv relations
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(*  Title       : Real/RealDef.thy
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    ID          : $Id$
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    Author      : Jacques D. Fleuriot
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    Copyright   : 1998  University of Cambridge
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    Conversion to Isar and new proofs by Lawrence C Paulson, 2003/4
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*)
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header{*Defining the Reals from the Positive Reals*}
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theory RealDef = PReal
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files ("real_arith.ML"):
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constdefs
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  realrel   ::  "((preal * preal) * (preal * preal)) set"
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  "realrel == {p. \<exists>x1 y1 x2 y2. p = ((x1,y1),(x2,y2)) & x1+y2 = x2+y1}"
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typedef (Real)  real = "UNIV//realrel"
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  by (auto simp add: quotient_def)
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instance real :: ord ..
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instance real :: zero ..
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instance real :: one ..
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instance real :: plus ..
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instance real :: times ..
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instance real :: minus ..
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instance real :: inverse ..
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constdefs
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  (** these don't use the overloaded "real" function: users don't see them **)
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  real_of_preal :: "preal => real"
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  "real_of_preal m     ==
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           Abs_Real(realrel``{(m + preal_of_rat 1, preal_of_rat 1)})"
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consts
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   (*Overloaded constant denoting the Real subset of enclosing
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     types such as hypreal and complex*)
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   Reals :: "'a set"
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   (*overloaded constant for injecting other types into "real"*)
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   real :: "'a => real"
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defs (overloaded)
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  real_zero_def:
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  "0 == Abs_Real(realrel``{(preal_of_rat 1, preal_of_rat 1)})"
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  real_one_def:
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  "1 == Abs_Real(realrel``
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               {(preal_of_rat 1 + preal_of_rat 1,
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		 preal_of_rat 1)})"
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  real_minus_def:
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  "- r ==  contents (\<Union>(x,y) \<in> Rep_Real(r). { Abs_Real(realrel``{(y,x)}) })"
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  real_add_def:
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   "z + w ==
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       contents (\<Union>(x,y) \<in> Rep_Real(z). \<Union>(u,v) \<in> Rep_Real(w).
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		 { Abs_Real(realrel``{(x+u, y+v)}) })"
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  real_diff_def:
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   "r - (s::real) == r + - s"
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  real_mult_def:
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    "z * w ==
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       contents (\<Union>(x,y) \<in> Rep_Real(z). \<Union>(u,v) \<in> Rep_Real(w).
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		 { Abs_Real(realrel``{(x*u + y*v, x*v + y*u)}) })"
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  real_inverse_def:
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  "inverse (R::real) == (SOME S. (R = 0 & S = 0) | S * R = 1)"
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  real_divide_def:
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  "R / (S::real) == R * inverse S"
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  real_le_def:
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   "z \<le> (w::real) == 
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    \<exists>x y u v. x+v \<le> u+y & (x,y) \<in> Rep_Real z & (u,v) \<in> Rep_Real w"
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  real_less_def: "(x < (y::real)) == (x \<le> y & x \<noteq> y)"
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  real_abs_def:  "abs (r::real) == (if 0 \<le> r then r else -r)"
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syntax (xsymbols)
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  Reals     :: "'a set"                   ("\<real>")
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subsection{*Proving that realrel is an equivalence relation*}
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lemma preal_trans_lemma:
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  assumes "x + y1 = x1 + y"
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      and "x + y2 = x2 + y"
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  shows "x1 + y2 = x2 + (y1::preal)"
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proof -
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  have "(x1 + y2) + x = (x + y2) + x1" by (simp add: preal_add_ac) 
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  also have "... = (x2 + y) + x1"  by (simp add: prems)
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  also have "... = x2 + (x1 + y)"  by (simp add: preal_add_ac)
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  also have "... = x2 + (x + y1)"  by (simp add: prems)
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  also have "... = (x2 + y1) + x"  by (simp add: preal_add_ac)
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  finally have "(x1 + y2) + x = (x2 + y1) + x" .
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  thus ?thesis by (simp add: preal_add_right_cancel_iff) 
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qed
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lemma realrel_iff [simp]: "(((x1,y1),(x2,y2)) \<in> realrel) = (x1 + y2 = x2 + y1)"
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by (simp add: realrel_def)
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lemma equiv_realrel: "equiv UNIV realrel"
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apply (auto simp add: equiv_def refl_def sym_def trans_def realrel_def)
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apply (blast dest: preal_trans_lemma) 
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done
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text{*Reduces equality of equivalence classes to the @{term realrel} relation:
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  @{term "(realrel `` {x} = realrel `` {y}) = ((x,y) \<in> realrel)"} *}
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lemmas equiv_realrel_iff = 
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       eq_equiv_class_iff [OF equiv_realrel UNIV_I UNIV_I]
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declare equiv_realrel_iff [simp]
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lemma realrel_in_real [simp]: "realrel``{(x,y)}: Real"
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by (simp add: Real_def realrel_def quotient_def, blast)
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lemma inj_on_Abs_Real: "inj_on Abs_Real Real"
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apply (rule inj_on_inverseI)
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apply (erule Abs_Real_inverse)
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done
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declare inj_on_Abs_Real [THEN inj_on_iff, simp]
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declare Abs_Real_inverse [simp]
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text{*Case analysis on the representation of a real number as an equivalence
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      class of pairs of positive reals.*}
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lemma eq_Abs_Real [case_names Abs_Real, cases type: real]: 
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     "(!!x y. z = Abs_Real(realrel``{(x,y)}) ==> P) ==> P"
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apply (rule Rep_Real [of z, unfolded Real_def, THEN quotientE])
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apply (drule arg_cong [where f=Abs_Real])
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apply (auto simp add: Rep_Real_inverse)
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done
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subsection{*Congruence property for addition*}
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lemma real_add_congruent2_lemma:
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     "[|a + ba = aa + b; ab + bc = ac + bb|]
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      ==> a + ab + (ba + bc) = aa + ac + (b + (bb::preal))"
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apply (simp add: preal_add_assoc) 
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apply (rule preal_add_left_commute [of ab, THEN ssubst])
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apply (simp add: preal_add_assoc [symmetric])
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apply (simp add: preal_add_ac)
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done
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lemma real_add:
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     "Abs_Real (realrel``{(x,y)}) + Abs_Real (realrel``{(u,v)}) =
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      Abs_Real (realrel``{(x+u, y+v)})"
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proof -
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  have "congruent2 realrel realrel
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        (\<lambda>z w. (\<lambda>(x,y). (\<lambda>(u,v). {Abs_Real (realrel `` {(x+u, y+v)})}) w) z)"
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    by (simp add: congruent2_def, blast intro: real_add_congruent2_lemma) 
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  thus ?thesis
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    by (simp add: real_add_def UN_UN_split_split_eq
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                  UN_equiv_class2 [OF equiv_realrel equiv_realrel])
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qed
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lemma real_add_commute: "(z::real) + w = w + z"
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by (cases z, cases w, simp add: real_add preal_add_ac)
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lemma real_add_assoc: "((z1::real) + z2) + z3 = z1 + (z2 + z3)"
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by (cases z1, cases z2, cases z3, simp add: real_add preal_add_assoc)
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lemma real_add_zero_left: "(0::real) + z = z"
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by (cases z, simp add: real_add real_zero_def preal_add_ac)
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instance real :: plus_ac0
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  by (intro_classes,
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      (assumption | 
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       rule real_add_commute real_add_assoc real_add_zero_left)+)
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subsection{*Additive Inverse on real*}
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lemma real_minus: "- Abs_Real(realrel``{(x,y)}) = Abs_Real(realrel `` {(y,x)})"
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proof -
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  have "congruent realrel (\<lambda>(x,y). {Abs_Real (realrel``{(y,x)})})"
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    by (simp add: congruent_def preal_add_commute) 
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  thus ?thesis
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    by (simp add: real_minus_def UN_equiv_class [OF equiv_realrel])
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qed
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lemma real_add_minus_left: "(-z) + z = (0::real)"
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by (cases z, simp add: real_minus real_add real_zero_def preal_add_commute)
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subsection{*Congruence property for multiplication*}
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lemma real_mult_congruent2_lemma:
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     "!!(x1::preal). [| x1 + y2 = x2 + y1 |] ==>
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          x * x1 + y * y1 + (x * y2 + y * x2) =
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          x * x2 + y * y2 + (x * y1 + y * x1)"
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apply (simp add: preal_add_left_commute preal_add_assoc [symmetric])
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apply (simp add: preal_add_assoc preal_add_mult_distrib2 [symmetric])
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apply (simp add: preal_add_commute)
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done
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lemma real_mult_congruent2:
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    "congruent2 realrel realrel (%p1 p2.
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        (%(x1,y1). (%(x2,y2). 
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          { Abs_Real (realrel``{(x1*x2 + y1*y2, x1*y2+y1*x2)}) }) p2) p1)"
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apply (rule congruent2_commuteI [OF equiv_realrel], clarify)
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apply (simp add: preal_mult_commute preal_add_commute)
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apply (auto simp add: real_mult_congruent2_lemma)
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done
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lemma real_mult:
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      "Abs_Real((realrel``{(x1,y1)})) * Abs_Real((realrel``{(x2,y2)})) =
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       Abs_Real(realrel `` {(x1*x2+y1*y2,x1*y2+y1*x2)})"
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by (simp add: real_mult_def UN_UN_split_split_eq
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         UN_equiv_class2 [OF equiv_realrel equiv_realrel real_mult_congruent2])
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lemma real_mult_commute: "(z::real) * w = w * z"
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by (cases z, cases w, simp add: real_mult preal_add_ac preal_mult_ac)
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lemma real_mult_assoc: "((z1::real) * z2) * z3 = z1 * (z2 * z3)"
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apply (cases z1, cases z2, cases z3)
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apply (simp add: real_mult preal_add_mult_distrib2 preal_add_ac preal_mult_ac)
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done
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lemma real_mult_1: "(1::real) * z = z"
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apply (cases z)
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apply (simp add: real_mult real_one_def preal_add_mult_distrib2
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                 preal_mult_1_right preal_mult_ac preal_add_ac)
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done
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lemma real_add_mult_distrib: "((z1::real) + z2) * w = (z1 * w) + (z2 * w)"
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apply (cases z1, cases z2, cases w)
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apply (simp add: real_add real_mult preal_add_mult_distrib2 
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                 preal_add_ac preal_mult_ac)
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done
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text{*one and zero are distinct*}
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lemma real_zero_not_eq_one: "0 \<noteq> (1::real)"
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proof -
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  have "preal_of_rat 1 < preal_of_rat 1 + preal_of_rat 1"
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    by (simp add: preal_self_less_add_left) 
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  thus ?thesis
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    by (simp add: real_zero_def real_one_def preal_add_right_cancel_iff)
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qed
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subsection{*existence of inverse*}
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lemma real_zero_iff: "Abs_Real (realrel `` {(x, x)}) = 0"
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by (simp add: real_zero_def preal_add_commute)
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text{*Instead of using an existential quantifier and constructing the inverse
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within the proof, we could define the inverse explicitly.*}
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lemma real_mult_inverse_left_ex: "x \<noteq> 0 ==> \<exists>y. y*x = (1::real)"
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apply (simp add: real_zero_def real_one_def, cases x)
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apply (cut_tac x = xa and y = y in linorder_less_linear)
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apply (auto dest!: less_add_left_Ex simp add: real_zero_iff)
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apply (rule_tac
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        x = "Abs_Real (realrel `` { (preal_of_rat 1, 
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                            inverse (D) + preal_of_rat 1)}) " 
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       in exI)
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apply (rule_tac [2]
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        x = "Abs_Real (realrel `` { (inverse (D) + preal_of_rat 1,
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                   preal_of_rat 1)})" 
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       in exI)
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apply (auto simp add: real_mult preal_mult_1_right
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              preal_add_mult_distrib2 preal_add_mult_distrib preal_mult_1
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              preal_mult_inverse_right preal_add_ac preal_mult_ac)
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done
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lemma real_mult_inverse_left: "x \<noteq> 0 ==> inverse(x)*x = (1::real)"
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apply (simp add: real_inverse_def)
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apply (frule real_mult_inverse_left_ex, safe)
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apply (rule someI2, auto)
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done
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subsection{*The Real Numbers form a Field*}
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instance real :: field
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proof
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  fix x y z :: real
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  show "(x + y) + z = x + (y + z)" by (rule real_add_assoc)
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  show "x + y = y + x" by (rule real_add_commute)
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  show "0 + x = x" by simp
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  show "- x + x = 0" by (rule real_add_minus_left)
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  show "x - y = x + (-y)" by (simp add: real_diff_def)
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  show "(x * y) * z = x * (y * z)" by (rule real_mult_assoc)
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  show "x * y = y * x" by (rule real_mult_commute)
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  show "1 * x = x" by (rule real_mult_1)
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  show "(x + y) * z = x * z + y * z" by (simp add: real_add_mult_distrib)
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  show "0 \<noteq> (1::real)" by (rule real_zero_not_eq_one)
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  show "x \<noteq> 0 ==> inverse x * x = 1" by (rule real_mult_inverse_left)
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  show "x / y = x * inverse y" by (simp add: real_divide_def)
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qed
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text{*Inverse of zero!  Useful to simplify certain equations*}
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lemma INVERSE_ZERO: "inverse 0 = (0::real)"
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by (simp add: real_inverse_def)
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instance real :: division_by_zero
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proof
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  show "inverse 0 = (0::real)" by (rule INVERSE_ZERO)
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qed
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paulson@14334
   315
paulson@14334
   316
(*Pull negations out*)
paulson@14334
   317
declare minus_mult_right [symmetric, simp] 
paulson@14334
   318
        minus_mult_left [symmetric, simp]
paulson@14334
   319
paulson@14334
   320
lemma real_mult_1_right: "z * (1::real) = z"
paulson@14334
   321
  by (rule Ring_and_Field.mult_1_right)
paulson@14269
   322
paulson@14269
   323
paulson@14365
   324
subsection{*The @{text "\<le>"} Ordering*}
paulson@14269
   325
paulson@14365
   326
lemma real_le_refl: "w \<le> (w::real)"
paulson@14484
   327
by (cases w, force simp add: real_le_def)
paulson@14269
   328
paulson@14378
   329
text{*The arithmetic decision procedure is not set up for type preal.
paulson@14378
   330
  This lemma is currently unused, but it could simplify the proofs of the
paulson@14378
   331
  following two lemmas.*}
paulson@14378
   332
lemma preal_eq_le_imp_le:
paulson@14378
   333
  assumes eq: "a+b = c+d" and le: "c \<le> a"
paulson@14378
   334
  shows "b \<le> (d::preal)"
paulson@14378
   335
proof -
paulson@14378
   336
  have "c+d \<le> a+d" by (simp add: prems preal_cancels)
paulson@14378
   337
  hence "a+b \<le> a+d" by (simp add: prems)
paulson@14378
   338
  thus "b \<le> d" by (simp add: preal_cancels)
paulson@14378
   339
qed
paulson@14378
   340
paulson@14378
   341
lemma real_le_lemma:
paulson@14378
   342
  assumes l: "u1 + v2 \<le> u2 + v1"
paulson@14378
   343
      and "x1 + v1 = u1 + y1"
paulson@14378
   344
      and "x2 + v2 = u2 + y2"
paulson@14378
   345
  shows "x1 + y2 \<le> x2 + (y1::preal)"
paulson@14365
   346
proof -
paulson@14378
   347
  have "(x1+v1) + (u2+y2) = (u1+y1) + (x2+v2)" by (simp add: prems)
paulson@14378
   348
  hence "(x1+y2) + (u2+v1) = (x2+y1) + (u1+v2)" by (simp add: preal_add_ac)
paulson@14378
   349
  also have "... \<le> (x2+y1) + (u2+v1)"
paulson@14365
   350
         by (simp add: prems preal_add_le_cancel_left)
paulson@14378
   351
  finally show ?thesis by (simp add: preal_add_le_cancel_right)
paulson@14378
   352
qed						 
paulson@14378
   353
paulson@14378
   354
lemma real_le: 
paulson@14484
   355
     "(Abs_Real(realrel``{(x1,y1)}) \<le> Abs_Real(realrel``{(x2,y2)})) =  
paulson@14484
   356
      (x1 + y2 \<le> x2 + y1)"
paulson@14378
   357
apply (simp add: real_le_def) 
paulson@14387
   358
apply (auto intro: real_le_lemma)
paulson@14378
   359
done
paulson@14378
   360
paulson@14378
   361
lemma real_le_anti_sym: "[| z \<le> w; w \<le> z |] ==> z = (w::real)"
paulson@14497
   362
by (cases z, cases w, simp add: real_le order_antisym)
paulson@14378
   363
paulson@14378
   364
lemma real_trans_lemma:
paulson@14378
   365
  assumes "x + v \<le> u + y"
paulson@14378
   366
      and "u + v' \<le> u' + v"
paulson@14378
   367
      and "x2 + v2 = u2 + y2"
paulson@14378
   368
  shows "x + v' \<le> u' + (y::preal)"
paulson@14378
   369
proof -
paulson@14378
   370
  have "(x+v') + (u+v) = (x+v) + (u+v')" by (simp add: preal_add_ac)
paulson@14378
   371
  also have "... \<le> (u+y) + (u+v')" 
paulson@14378
   372
    by (simp add: preal_add_le_cancel_right prems) 
paulson@14378
   373
  also have "... \<le> (u+y) + (u'+v)" 
paulson@14378
   374
    by (simp add: preal_add_le_cancel_left prems) 
paulson@14378
   375
  also have "... = (u'+y) + (u+v)"  by (simp add: preal_add_ac)
paulson@14378
   376
  finally show ?thesis by (simp add: preal_add_le_cancel_right)
paulson@14365
   377
qed						 
paulson@14269
   378
paulson@14365
   379
lemma real_le_trans: "[| i \<le> j; j \<le> k |] ==> i \<le> (k::real)"
paulson@14484
   380
apply (cases i, cases j, cases k)
paulson@14484
   381
apply (simp add: real_le)
paulson@14378
   382
apply (blast intro: real_trans_lemma) 
paulson@14334
   383
done
paulson@14334
   384
paulson@14334
   385
(* Axiom 'order_less_le' of class 'order': *)
paulson@14334
   386
lemma real_less_le: "((w::real) < z) = (w \<le> z & w \<noteq> z)"
paulson@14365
   387
by (simp add: real_less_def)
paulson@14365
   388
paulson@14365
   389
instance real :: order
paulson@14365
   390
proof qed
paulson@14365
   391
 (assumption |
paulson@14365
   392
  rule real_le_refl real_le_trans real_le_anti_sym real_less_le)+
paulson@14365
   393
paulson@14378
   394
(* Axiom 'linorder_linear' of class 'linorder': *)
paulson@14378
   395
lemma real_le_linear: "(z::real) \<le> w | w \<le> z"
paulson@14484
   396
apply (cases z, cases w) 
paulson@14378
   397
apply (auto simp add: real_le real_zero_def preal_add_ac preal_cancels)
paulson@14334
   398
done
paulson@14334
   399
paulson@14334
   400
paulson@14334
   401
instance real :: linorder
paulson@14334
   402
  by (intro_classes, rule real_le_linear)
paulson@14334
   403
paulson@14334
   404
paulson@14378
   405
lemma real_le_eq_diff: "(x \<le> y) = (x-y \<le> (0::real))"
paulson@14484
   406
apply (cases x, cases y) 
paulson@14378
   407
apply (auto simp add: real_le real_zero_def real_diff_def real_add real_minus
paulson@14378
   408
                      preal_add_ac)
paulson@14378
   409
apply (simp_all add: preal_add_assoc [symmetric] preal_cancels)
paulson@14378
   410
done 
paulson@14378
   411
paulson@14484
   412
lemma real_add_left_mono: 
paulson@14484
   413
  assumes le: "x \<le> y" shows "z + x \<le> z + (y::real)"
paulson@14484
   414
proof -
paulson@14484
   415
  have "z + x - (z + y) = (z + -z) + (x - y)"
paulson@14484
   416
    by (simp add: diff_minus add_ac) 
paulson@14484
   417
  with le show ?thesis 
paulson@14484
   418
    by (simp add: real_le_eq_diff [of x] real_le_eq_diff [of "z+x"])
paulson@14484
   419
qed
paulson@14334
   420
paulson@14365
   421
lemma real_sum_gt_zero_less: "(0 < S + (-W::real)) ==> (W < S)"
paulson@14365
   422
by (simp add: linorder_not_le [symmetric] real_le_eq_diff [of S] diff_minus)
paulson@14365
   423
paulson@14365
   424
lemma real_less_sum_gt_zero: "(W < S) ==> (0 < S + (-W::real))"
paulson@14365
   425
by (simp add: linorder_not_le [symmetric] real_le_eq_diff [of S] diff_minus)
paulson@14334
   426
paulson@14334
   427
lemma real_mult_order: "[| 0 < x; 0 < y |] ==> (0::real) < x * y"
paulson@14484
   428
apply (cases x, cases y)
paulson@14378
   429
apply (simp add: linorder_not_le [where 'a = real, symmetric] 
paulson@14378
   430
                 linorder_not_le [where 'a = preal] 
paulson@14378
   431
                  real_zero_def real_le real_mult)
paulson@14365
   432
  --{*Reduce to the (simpler) @{text "\<le>"} relation *}
paulson@14378
   433
apply (auto  dest!: less_add_left_Ex 
paulson@14365
   434
     simp add: preal_add_ac preal_mult_ac 
paulson@14378
   435
          preal_add_mult_distrib2 preal_cancels preal_self_less_add_right)
paulson@14334
   436
done
paulson@14334
   437
paulson@14334
   438
lemma real_mult_less_mono2: "[| (0::real) < z; x < y |] ==> z * x < z * y"
paulson@14334
   439
apply (rule real_sum_gt_zero_less)
paulson@14334
   440
apply (drule real_less_sum_gt_zero [of x y])
paulson@14334
   441
apply (drule real_mult_order, assumption)
paulson@14334
   442
apply (simp add: right_distrib)
paulson@14334
   443
done
paulson@14334
   444
paulson@14365
   445
text{*lemma for proving @{term "0<(1::real)"}*}
paulson@14365
   446
lemma real_zero_le_one: "0 \<le> (1::real)"
paulson@14387
   447
by (simp add: real_zero_def real_one_def real_le 
paulson@14378
   448
                 preal_self_less_add_left order_less_imp_le)
paulson@14334
   449
paulson@14378
   450
paulson@14334
   451
subsection{*The Reals Form an Ordered Field*}
paulson@14334
   452
paulson@14334
   453
instance real :: ordered_field
paulson@14334
   454
proof
paulson@14334
   455
  fix x y z :: real
paulson@14334
   456
  show "x \<le> y ==> z + x \<le> z + y" by (rule real_add_left_mono)
paulson@14334
   457
  show "x < y ==> 0 < z ==> z * x < z * y" by (simp add: real_mult_less_mono2)
paulson@14334
   458
  show "\<bar>x\<bar> = (if x < 0 then -x else x)"
paulson@14334
   459
    by (auto dest: order_le_less_trans simp add: real_abs_def linorder_not_le)
paulson@14334
   460
qed
paulson@14334
   461
paulson@14365
   462
paulson@14365
   463
paulson@14365
   464
text{*The function @{term real_of_preal} requires many proofs, but it seems
paulson@14365
   465
to be essential for proving completeness of the reals from that of the
paulson@14365
   466
positive reals.*}
paulson@14365
   467
paulson@14365
   468
lemma real_of_preal_add:
paulson@14365
   469
     "real_of_preal ((x::preal) + y) = real_of_preal x + real_of_preal y"
paulson@14365
   470
by (simp add: real_of_preal_def real_add preal_add_mult_distrib preal_mult_1 
paulson@14365
   471
              preal_add_ac)
paulson@14365
   472
paulson@14365
   473
lemma real_of_preal_mult:
paulson@14365
   474
     "real_of_preal ((x::preal) * y) = real_of_preal x* real_of_preal y"
paulson@14365
   475
by (simp add: real_of_preal_def real_mult preal_add_mult_distrib2
paulson@14365
   476
              preal_mult_1 preal_mult_1_right preal_add_ac preal_mult_ac)
paulson@14365
   477
paulson@14365
   478
paulson@14365
   479
text{*Gleason prop 9-4.4 p 127*}
paulson@14365
   480
lemma real_of_preal_trichotomy:
paulson@14365
   481
      "\<exists>m. (x::real) = real_of_preal m | x = 0 | x = -(real_of_preal m)"
paulson@14484
   482
apply (simp add: real_of_preal_def real_zero_def, cases x)
paulson@14365
   483
apply (auto simp add: real_minus preal_add_ac)
paulson@14365
   484
apply (cut_tac x = x and y = y in linorder_less_linear)
paulson@14365
   485
apply (auto dest!: less_add_left_Ex simp add: preal_add_assoc [symmetric])
paulson@14365
   486
apply (auto simp add: preal_add_commute)
paulson@14365
   487
done
paulson@14365
   488
paulson@14365
   489
lemma real_of_preal_leD:
paulson@14365
   490
      "real_of_preal m1 \<le> real_of_preal m2 ==> m1 \<le> m2"
paulson@14484
   491
by (simp add: real_of_preal_def real_le preal_cancels)
paulson@14365
   492
paulson@14365
   493
lemma real_of_preal_lessI: "m1 < m2 ==> real_of_preal m1 < real_of_preal m2"
paulson@14365
   494
by (auto simp add: real_of_preal_leD linorder_not_le [symmetric])
paulson@14365
   495
paulson@14365
   496
lemma real_of_preal_lessD:
paulson@14365
   497
      "real_of_preal m1 < real_of_preal m2 ==> m1 < m2"
paulson@14484
   498
by (simp add: real_of_preal_def real_le linorder_not_le [symmetric] 
paulson@14484
   499
              preal_cancels) 
paulson@14484
   500
paulson@14365
   501
paulson@14365
   502
lemma real_of_preal_less_iff [simp]:
paulson@14365
   503
     "(real_of_preal m1 < real_of_preal m2) = (m1 < m2)"
paulson@14365
   504
by (blast intro: real_of_preal_lessI real_of_preal_lessD)
paulson@14365
   505
paulson@14365
   506
lemma real_of_preal_le_iff:
paulson@14365
   507
     "(real_of_preal m1 \<le> real_of_preal m2) = (m1 \<le> m2)"
paulson@14365
   508
by (simp add: linorder_not_less [symmetric]) 
paulson@14365
   509
paulson@14365
   510
lemma real_of_preal_zero_less: "0 < real_of_preal m"
paulson@14365
   511
apply (auto simp add: real_zero_def real_of_preal_def real_less_def real_le_def
paulson@14365
   512
            preal_add_ac preal_cancels)
paulson@14365
   513
apply (simp_all add: preal_add_assoc [symmetric] preal_cancels)
paulson@14365
   514
apply (blast intro: preal_self_less_add_left order_less_imp_le)
paulson@14365
   515
apply (insert preal_not_eq_self [of "preal_of_rat 1" m]) 
paulson@14365
   516
apply (simp add: preal_add_ac) 
paulson@14365
   517
done
paulson@14365
   518
paulson@14365
   519
lemma real_of_preal_minus_less_zero: "- real_of_preal m < 0"
paulson@14365
   520
by (simp add: real_of_preal_zero_less)
paulson@14365
   521
paulson@14365
   522
lemma real_of_preal_not_minus_gt_zero: "~ 0 < - real_of_preal m"
paulson@14484
   523
proof -
paulson@14484
   524
  from real_of_preal_minus_less_zero
paulson@14484
   525
  show ?thesis by (blast dest: order_less_trans)
paulson@14484
   526
qed
paulson@14365
   527
paulson@14365
   528
paulson@14365
   529
subsection{*Theorems About the Ordering*}
paulson@14365
   530
paulson@14365
   531
text{*obsolete but used a lot*}
paulson@14365
   532
paulson@14365
   533
lemma real_not_refl2: "x < y ==> x \<noteq> (y::real)"
paulson@14365
   534
by blast 
paulson@14365
   535
paulson@14365
   536
lemma real_le_imp_less_or_eq: "!!(x::real). x \<le> y ==> x < y | x = y"
paulson@14365
   537
by (simp add: order_le_less)
paulson@14365
   538
paulson@14365
   539
lemma real_gt_zero_preal_Ex: "(0 < x) = (\<exists>y. x = real_of_preal y)"
paulson@14365
   540
apply (auto simp add: real_of_preal_zero_less)
paulson@14365
   541
apply (cut_tac x = x in real_of_preal_trichotomy)
paulson@14365
   542
apply (blast elim!: real_of_preal_not_minus_gt_zero [THEN notE])
paulson@14365
   543
done
paulson@14365
   544
paulson@14365
   545
lemma real_gt_preal_preal_Ex:
paulson@14365
   546
     "real_of_preal z < x ==> \<exists>y. x = real_of_preal y"
paulson@14365
   547
by (blast dest!: real_of_preal_zero_less [THEN order_less_trans]
paulson@14365
   548
             intro: real_gt_zero_preal_Ex [THEN iffD1])
paulson@14365
   549
paulson@14365
   550
lemma real_ge_preal_preal_Ex:
paulson@14365
   551
     "real_of_preal z \<le> x ==> \<exists>y. x = real_of_preal y"
paulson@14365
   552
by (blast dest: order_le_imp_less_or_eq real_gt_preal_preal_Ex)
paulson@14365
   553
paulson@14365
   554
lemma real_less_all_preal: "y \<le> 0 ==> \<forall>x. y < real_of_preal x"
paulson@14365
   555
by (auto elim: order_le_imp_less_or_eq [THEN disjE] 
paulson@14365
   556
            intro: real_of_preal_zero_less [THEN [2] order_less_trans] 
paulson@14365
   557
            simp add: real_of_preal_zero_less)
paulson@14365
   558
paulson@14365
   559
lemma real_less_all_real2: "~ 0 < y ==> \<forall>x. y < real_of_preal x"
paulson@14365
   560
by (blast intro!: real_less_all_preal linorder_not_less [THEN iffD1])
paulson@14365
   561
paulson@14334
   562
lemma real_add_less_le_mono: "[| w'<w; z'\<le>z |] ==> w' + z' < w + (z::real)"
paulson@14365
   563
  by (rule Ring_and_Field.add_less_le_mono)
paulson@14334
   564
paulson@14334
   565
lemma real_add_le_less_mono:
paulson@14334
   566
     "!!z z'::real. [| w'\<le>w; z'<z |] ==> w' + z' < w + z"
paulson@14365
   567
  by (rule Ring_and_Field.add_le_less_mono)
paulson@14334
   568
paulson@14334
   569
lemma real_le_square [simp]: "(0::real) \<le> x*x"
paulson@14334
   570
 by (rule Ring_and_Field.zero_le_square)
paulson@14334
   571
paulson@14334
   572
paulson@14334
   573
subsection{*More Lemmas*}
paulson@14334
   574
paulson@14334
   575
lemma real_mult_left_cancel: "(c::real) \<noteq> 0 ==> (c*a=c*b) = (a=b)"
paulson@14334
   576
by auto
paulson@14334
   577
paulson@14334
   578
lemma real_mult_right_cancel: "(c::real) \<noteq> 0 ==> (a*c=b*c) = (a=b)"
paulson@14334
   579
by auto
paulson@14334
   580
paulson@14334
   581
text{*The precondition could be weakened to @{term "0\<le>x"}*}
paulson@14334
   582
lemma real_mult_less_mono:
paulson@14334
   583
     "[| u<v;  x<y;  (0::real) < v;  0 < x |] ==> u*x < v* y"
paulson@14334
   584
 by (simp add: Ring_and_Field.mult_strict_mono order_less_imp_le)
paulson@14334
   585
paulson@14334
   586
lemma real_mult_less_iff1 [simp]: "(0::real) < z ==> (x*z < y*z) = (x < y)"
paulson@14334
   587
  by (force elim: order_less_asym
paulson@14334
   588
            simp add: Ring_and_Field.mult_less_cancel_right)
paulson@14334
   589
paulson@14334
   590
lemma real_mult_le_cancel_iff1 [simp]: "(0::real) < z ==> (x*z \<le> y*z) = (x\<le>y)"
paulson@14365
   591
apply (simp add: mult_le_cancel_right)
paulson@14365
   592
apply (blast intro: elim: order_less_asym) 
paulson@14365
   593
done
paulson@14334
   594
paulson@14334
   595
lemma real_mult_le_cancel_iff2 [simp]: "(0::real) < z ==> (z*x \<le> z*y) = (x\<le>y)"
paulson@14334
   596
  by (force elim: order_less_asym
paulson@14334
   597
            simp add: Ring_and_Field.mult_le_cancel_left)
paulson@14334
   598
paulson@14334
   599
text{*Only two uses?*}
paulson@14334
   600
lemma real_mult_less_mono':
paulson@14334
   601
     "[| x < y;  r1 < r2;  (0::real) \<le> r1;  0 \<le> x|] ==> r1 * x < r2 * y"
paulson@14334
   602
 by (rule Ring_and_Field.mult_strict_mono')
paulson@14334
   603
paulson@14334
   604
text{*FIXME: delete or at least combine the next two lemmas*}
paulson@14334
   605
lemma real_sum_squares_cancel: "x * x + y * y = 0 ==> x = (0::real)"
paulson@14334
   606
apply (drule Ring_and_Field.equals_zero_I [THEN sym])
paulson@14334
   607
apply (cut_tac x = y in real_le_square) 
paulson@14476
   608
apply (auto, drule order_antisym, auto)
paulson@14334
   609
done
paulson@14334
   610
paulson@14334
   611
lemma real_sum_squares_cancel2: "x * x + y * y = 0 ==> y = (0::real)"
paulson@14334
   612
apply (rule_tac y = x in real_sum_squares_cancel)
paulson@14476
   613
apply (simp add: add_commute)
paulson@14334
   614
done
paulson@14334
   615
paulson@14334
   616
lemma real_add_order: "[| 0 < x; 0 < y |] ==> (0::real) < x + y"
paulson@14365
   617
by (drule add_strict_mono [of concl: 0 0], assumption, simp)
paulson@14334
   618
paulson@14334
   619
lemma real_le_add_order: "[| 0 \<le> x; 0 \<le> y |] ==> (0::real) \<le> x + y"
paulson@14334
   620
apply (drule order_le_imp_less_or_eq)+
paulson@14334
   621
apply (auto intro: real_add_order order_less_imp_le)
paulson@14334
   622
done
paulson@14334
   623
paulson@14365
   624
lemma real_inverse_unique: "x*y = (1::real) ==> y = inverse x"
paulson@14365
   625
apply (case_tac "x \<noteq> 0")
paulson@14365
   626
apply (rule_tac c1 = x in real_mult_left_cancel [THEN iffD1], auto)
paulson@14365
   627
done
paulson@14334
   628
paulson@14365
   629
lemma real_inverse_gt_one: "[| (0::real) < x; x < 1 |] ==> 1 < inverse x"
paulson@14365
   630
by (auto dest: less_imp_inverse_less)
paulson@14334
   631
paulson@14365
   632
lemma real_mult_self_sum_ge_zero: "(0::real) \<le> x*x + y*y"
paulson@14365
   633
proof -
paulson@14365
   634
  have "0 + 0 \<le> x*x + y*y" by (blast intro: add_mono zero_le_square)
paulson@14365
   635
  thus ?thesis by simp
paulson@14365
   636
qed
paulson@14365
   637
paulson@14334
   638
paulson@14365
   639
subsection{*Embedding the Integers into the Reals*}
paulson@14365
   640
paulson@14378
   641
defs (overloaded)
paulson@14378
   642
  real_of_nat_def: "real z == of_nat z"
paulson@14378
   643
  real_of_int_def: "real z == of_int z"
paulson@14365
   644
paulson@14365
   645
lemma real_of_int_zero [simp]: "real (0::int) = 0"  
paulson@14378
   646
by (simp add: real_of_int_def) 
paulson@14365
   647
paulson@14365
   648
lemma real_of_one [simp]: "real (1::int) = (1::real)"
paulson@14378
   649
by (simp add: real_of_int_def) 
paulson@14334
   650
paulson@14365
   651
lemma real_of_int_add: "real (x::int) + real y = real (x + y)"
paulson@14378
   652
by (simp add: real_of_int_def) 
paulson@14365
   653
declare real_of_int_add [symmetric, simp]
paulson@14365
   654
paulson@14365
   655
lemma real_of_int_minus: "-real (x::int) = real (-x)"
paulson@14378
   656
by (simp add: real_of_int_def) 
paulson@14365
   657
declare real_of_int_minus [symmetric, simp]
paulson@14365
   658
paulson@14365
   659
lemma real_of_int_diff: "real (x::int) - real y = real (x - y)"
paulson@14378
   660
by (simp add: real_of_int_def) 
paulson@14365
   661
declare real_of_int_diff [symmetric, simp]
paulson@14334
   662
paulson@14365
   663
lemma real_of_int_mult: "real (x::int) * real y = real (x * y)"
paulson@14378
   664
by (simp add: real_of_int_def) 
paulson@14365
   665
declare real_of_int_mult [symmetric, simp]
paulson@14365
   666
paulson@14365
   667
lemma real_of_int_zero_cancel [simp]: "(real x = 0) = (x = (0::int))"
paulson@14378
   668
by (simp add: real_of_int_def) 
paulson@14365
   669
paulson@14365
   670
lemma real_of_int_inject [iff]: "(real (x::int) = real y) = (x = y)"
paulson@14378
   671
by (simp add: real_of_int_def) 
paulson@14365
   672
paulson@14365
   673
lemma real_of_int_less_iff [iff]: "(real (x::int) < real y) = (x < y)"
paulson@14378
   674
by (simp add: real_of_int_def) 
paulson@14365
   675
paulson@14365
   676
lemma real_of_int_le_iff [simp]: "(real (x::int) \<le> real y) = (x \<le> y)"
paulson@14378
   677
by (simp add: real_of_int_def) 
paulson@14365
   678
paulson@14365
   679
paulson@14365
   680
subsection{*Embedding the Naturals into the Reals*}
paulson@14365
   681
paulson@14334
   682
lemma real_of_nat_zero [simp]: "real (0::nat) = 0"
paulson@14365
   683
by (simp add: real_of_nat_def)
paulson@14334
   684
paulson@14334
   685
lemma real_of_nat_one [simp]: "real (Suc 0) = (1::real)"
paulson@14365
   686
by (simp add: real_of_nat_def)
paulson@14334
   687
paulson@14365
   688
lemma real_of_nat_add [simp]: "real (m + n) = real (m::nat) + real n"
paulson@14378
   689
by (simp add: real_of_nat_def)
paulson@14334
   690
paulson@14334
   691
(*Not for addsimps: often the LHS is used to represent a positive natural*)
paulson@14334
   692
lemma real_of_nat_Suc: "real (Suc n) = real n + (1::real)"
paulson@14378
   693
by (simp add: real_of_nat_def)
paulson@14334
   694
paulson@14334
   695
lemma real_of_nat_less_iff [iff]: 
paulson@14334
   696
     "(real (n::nat) < real m) = (n < m)"
paulson@14365
   697
by (simp add: real_of_nat_def)
paulson@14334
   698
paulson@14334
   699
lemma real_of_nat_le_iff [iff]: "(real (n::nat) \<le> real m) = (n \<le> m)"
paulson@14378
   700
by (simp add: real_of_nat_def)
paulson@14334
   701
paulson@14334
   702
lemma real_of_nat_ge_zero [iff]: "0 \<le> real (n::nat)"
paulson@14378
   703
by (simp add: real_of_nat_def zero_le_imp_of_nat)
paulson@14334
   704
paulson@14365
   705
lemma real_of_nat_Suc_gt_zero: "0 < real (Suc n)"
paulson@14378
   706
by (simp add: real_of_nat_def del: of_nat_Suc)
paulson@14365
   707
paulson@14334
   708
lemma real_of_nat_mult [simp]: "real (m * n) = real (m::nat) * real n"
paulson@14378
   709
by (simp add: real_of_nat_def)
paulson@14334
   710
paulson@14334
   711
lemma real_of_nat_inject [iff]: "(real (n::nat) = real m) = (n = m)"
paulson@14378
   712
by (simp add: real_of_nat_def)
paulson@14334
   713
paulson@14387
   714
lemma real_of_nat_zero_iff [iff]: "(real (n::nat) = 0) = (n = 0)"
paulson@14378
   715
by (simp add: real_of_nat_def)
paulson@14334
   716
paulson@14365
   717
lemma real_of_nat_diff: "n \<le> m ==> real (m - n) = real (m::nat) - real n"
paulson@14378
   718
by (simp add: add: real_of_nat_def) 
paulson@14334
   719
paulson@14365
   720
lemma real_of_nat_gt_zero_cancel_iff [simp]: "(0 < real (n::nat)) = (0 < n)"
paulson@14378
   721
by (simp add: add: real_of_nat_def) 
paulson@14365
   722
paulson@14365
   723
lemma real_of_nat_le_zero_cancel_iff [simp]: "(real (n::nat) \<le> 0) = (n = 0)"
paulson@14378
   724
by (simp add: add: real_of_nat_def)
paulson@14334
   725
paulson@14365
   726
lemma not_real_of_nat_less_zero [simp]: "~ real (n::nat) < 0"
paulson@14378
   727
by (simp add: add: real_of_nat_def)
paulson@14334
   728
paulson@14365
   729
lemma real_of_nat_ge_zero_cancel_iff [simp]: "(0 \<le> real (n::nat)) = (0 \<le> n)"
paulson@14378
   730
by (simp add: add: real_of_nat_def)
paulson@14334
   731
paulson@14365
   732
lemma real_of_int_real_of_nat: "real (int n) = real n"
paulson@14378
   733
by (simp add: real_of_nat_def real_of_int_def int_eq_of_nat)
paulson@14378
   734
paulson@14426
   735
lemma real_of_int_of_nat_eq [simp]: "real (of_nat n :: int) = real n"
paulson@14426
   736
by (simp add: real_of_int_def real_of_nat_def)
paulson@14334
   737
paulson@14387
   738
paulson@14387
   739
paulson@14387
   740
subsection{*Numerals and Arithmetic*}
paulson@14387
   741
paulson@14387
   742
instance real :: number ..
paulson@14387
   743
paulson@14387
   744
primrec (*the type constraint is essential!*)
paulson@14387
   745
  number_of_Pls: "number_of bin.Pls = 0"
paulson@14387
   746
  number_of_Min: "number_of bin.Min = - (1::real)"
paulson@14387
   747
  number_of_BIT: "number_of(w BIT x) = (if x then 1 else 0) +
paulson@14387
   748
	                               (number_of w) + (number_of w)"
paulson@14387
   749
paulson@14387
   750
declare number_of_Pls [simp del]
paulson@14387
   751
        number_of_Min [simp del]
paulson@14387
   752
        number_of_BIT [simp del]
paulson@14387
   753
paulson@14387
   754
instance real :: number_ring
paulson@14387
   755
proof
paulson@14387
   756
  show "Numeral0 = (0::real)" by (rule number_of_Pls)
paulson@14387
   757
  show "-1 = - (1::real)" by (rule number_of_Min)
paulson@14387
   758
  fix w :: bin and x :: bool
paulson@14387
   759
  show "(number_of (w BIT x) :: real) =
paulson@14387
   760
        (if x then 1 else 0) + number_of w + number_of w"
paulson@14387
   761
    by (rule number_of_BIT)
paulson@14387
   762
qed
paulson@14387
   763
paulson@14387
   764
paulson@14387
   765
text{*Collapse applications of @{term real} to @{term number_of}*}
paulson@14387
   766
lemma real_number_of [simp]: "real (number_of v :: int) = number_of v"
paulson@14387
   767
by (simp add:  real_of_int_def of_int_number_of_eq)
paulson@14387
   768
paulson@14387
   769
lemma real_of_nat_number_of [simp]:
paulson@14387
   770
     "real (number_of v :: nat) =  
paulson@14387
   771
        (if neg (number_of v :: int) then 0  
paulson@14387
   772
         else (number_of v :: real))"
paulson@14387
   773
by (simp add: real_of_int_real_of_nat [symmetric] int_nat_number_of)
paulson@14387
   774
 
paulson@14387
   775
paulson@14387
   776
use "real_arith.ML"
paulson@14387
   777
paulson@14387
   778
setup real_arith_setup
paulson@14387
   779
paulson@14387
   780
subsection{* Simprules combining x+y and 0: ARE THEY NEEDED?*}
paulson@14387
   781
paulson@14387
   782
text{*Needed in this non-standard form by Hyperreal/Transcendental*}
paulson@14387
   783
lemma real_0_le_divide_iff:
paulson@14387
   784
     "((0::real) \<le> x/y) = ((x \<le> 0 | 0 \<le> y) & (0 \<le> x | y \<le> 0))"
paulson@14387
   785
by (simp add: real_divide_def zero_le_mult_iff, auto)
paulson@14387
   786
paulson@14387
   787
lemma real_add_minus_iff [simp]: "(x + - a = (0::real)) = (x=a)" 
paulson@14387
   788
by arith
paulson@14387
   789
paulson@14387
   790
lemma real_add_eq_0_iff [iff]: "(x+y = (0::real)) = (y = -x)"
paulson@14387
   791
by auto
paulson@14387
   792
paulson@14387
   793
lemma real_add_less_0_iff [iff]: "(x+y < (0::real)) = (y < -x)"
paulson@14387
   794
by auto
paulson@14387
   795
paulson@14387
   796
lemma real_0_less_add_iff [iff]: "((0::real) < x+y) = (-x < y)"
paulson@14387
   797
by auto
paulson@14387
   798
paulson@14387
   799
lemma real_add_le_0_iff [iff]: "(x+y \<le> (0::real)) = (y \<le> -x)"
paulson@14387
   800
by auto
paulson@14387
   801
paulson@14387
   802
lemma real_0_le_add_iff [iff]: "((0::real) \<le> x+y) = (-x \<le> y)"
paulson@14387
   803
by auto
paulson@14387
   804
paulson@14387
   805
paulson@14387
   806
(** Simprules combining x-y and 0 (needed??) **)
paulson@14387
   807
paulson@14387
   808
lemma real_0_less_diff_iff [iff]: "((0::real) < x-y) = (y < x)"
paulson@14387
   809
by auto
paulson@14387
   810
paulson@14387
   811
lemma real_0_le_diff_iff [iff]: "((0::real) \<le> x-y) = (y \<le> x)"
paulson@14387
   812
by auto
paulson@14387
   813
paulson@14387
   814
(*
paulson@14387
   815
FIXME: we should have this, as for type int, but many proofs would break.
paulson@14387
   816
It replaces x+-y by x-y.
paulson@14387
   817
Addsimps [symmetric real_diff_def]
paulson@14387
   818
*)
paulson@14387
   819
paulson@14387
   820
paulson@14387
   821
subsubsection{*Density of the Reals*}
paulson@14387
   822
paulson@14387
   823
lemma real_lbound_gt_zero:
paulson@14387
   824
     "[| (0::real) < d1; 0 < d2 |] ==> \<exists>e. 0 < e & e < d1 & e < d2"
paulson@14387
   825
apply (rule_tac x = " (min d1 d2) /2" in exI)
paulson@14387
   826
apply (simp add: min_def)
paulson@14387
   827
done
paulson@14387
   828
paulson@14387
   829
paulson@14387
   830
text{*Similar results are proved in @{text Ring_and_Field}*}
paulson@14387
   831
lemma real_less_half_sum: "x < y ==> x < (x+y) / (2::real)"
paulson@14387
   832
  by auto
paulson@14387
   833
paulson@14387
   834
lemma real_gt_half_sum: "x < y ==> (x+y)/(2::real) < y"
paulson@14387
   835
  by auto
paulson@14387
   836
paulson@14387
   837
paulson@14387
   838
subsection{*Absolute Value Function for the Reals*}
paulson@14387
   839
paulson@14387
   840
text{*FIXME: these should go!*}
paulson@14387
   841
lemma abs_eqI1: "(0::real)\<le>x ==> abs x = x"
paulson@14484
   842
by (simp add: real_abs_def)
paulson@14387
   843
paulson@14387
   844
lemma abs_eqI2: "(0::real) < x ==> abs x = x"
paulson@14484
   845
by (simp add: real_abs_def)
paulson@14387
   846
paulson@14387
   847
lemma abs_minus_eqI2: "x < (0::real) ==> abs x = -x"
paulson@14387
   848
by (simp add: real_abs_def linorder_not_less [symmetric])
paulson@14387
   849
paulson@14387
   850
lemma abs_minus_add_cancel: "abs(x + (-y)) = abs (y + (-(x::real)))"
paulson@14484
   851
by (simp add: real_abs_def)
paulson@14387
   852
paulson@14387
   853
lemma abs_interval_iff: "(abs x < r) = (-r < x & x < (r::real))"
paulson@14387
   854
by (force simp add: Ring_and_Field.abs_less_iff)
paulson@14387
   855
paulson@14387
   856
lemma abs_le_interval_iff: "(abs x \<le> r) = (-r\<le>x & x\<le>(r::real))"
paulson@14387
   857
by (force simp add: Ring_and_Field.abs_le_iff)
paulson@14387
   858
paulson@14484
   859
(*FIXME: used only once, in SEQ.ML*)
paulson@14387
   860
lemma abs_add_one_gt_zero [simp]: "(0::real) < 1 + abs(x)"
paulson@14484
   861
by (simp add: real_abs_def)
paulson@14387
   862
paulson@14387
   863
lemma abs_real_of_nat_cancel [simp]: "abs (real x) = real (x::nat)"
paulson@14387
   864
by (auto intro: abs_eqI1 simp add: real_of_nat_ge_zero)
paulson@14387
   865
paulson@14387
   866
lemma abs_add_one_not_less_self [simp]: "~ abs(x) + (1::real) < x"
paulson@14387
   867
apply (simp add: linorder_not_less)
paulson@14387
   868
apply (auto intro: abs_ge_self [THEN order_trans])
paulson@14387
   869
done
paulson@14387
   870
 
paulson@14387
   871
text{*Used only in Hyperreal/Lim.ML*}
paulson@14387
   872
lemma abs_sum_triangle_ineq: "abs ((x::real) + y + (-l + -m)) \<le> abs(x + -l) + abs(y + -m)"
paulson@14387
   873
apply (simp add: real_add_assoc)
paulson@14387
   874
apply (rule_tac a1 = y in add_left_commute [THEN ssubst])
paulson@14387
   875
apply (rule real_add_assoc [THEN subst])
paulson@14387
   876
apply (rule abs_triangle_ineq)
paulson@14387
   877
done
paulson@14387
   878
paulson@14387
   879
paulson@14387
   880
paulson@14334
   881
ML
paulson@14334
   882
{*
paulson@14387
   883
val real_0_le_divide_iff = thm"real_0_le_divide_iff";
paulson@14387
   884
val real_add_minus_iff = thm"real_add_minus_iff";
paulson@14387
   885
val real_add_eq_0_iff = thm"real_add_eq_0_iff";
paulson@14387
   886
val real_add_less_0_iff = thm"real_add_less_0_iff";
paulson@14387
   887
val real_0_less_add_iff = thm"real_0_less_add_iff";
paulson@14387
   888
val real_add_le_0_iff = thm"real_add_le_0_iff";
paulson@14387
   889
val real_0_le_add_iff = thm"real_0_le_add_iff";
paulson@14387
   890
val real_0_less_diff_iff = thm"real_0_less_diff_iff";
paulson@14387
   891
val real_0_le_diff_iff = thm"real_0_le_diff_iff";
paulson@14387
   892
val real_lbound_gt_zero = thm"real_lbound_gt_zero";
paulson@14387
   893
val real_less_half_sum = thm"real_less_half_sum";
paulson@14387
   894
val real_gt_half_sum = thm"real_gt_half_sum";
paulson@14341
   895
paulson@14387
   896
val abs_eqI1 = thm"abs_eqI1";
paulson@14387
   897
val abs_eqI2 = thm"abs_eqI2";
paulson@14387
   898
val abs_minus_eqI2 = thm"abs_minus_eqI2";
paulson@14387
   899
val abs_ge_zero = thm"abs_ge_zero";
paulson@14387
   900
val abs_idempotent = thm"abs_idempotent";
paulson@14387
   901
val abs_zero_iff = thm"abs_zero_iff";
paulson@14387
   902
val abs_ge_self = thm"abs_ge_self";
paulson@14387
   903
val abs_ge_minus_self = thm"abs_ge_minus_self";
paulson@14387
   904
val abs_mult = thm"abs_mult";
paulson@14387
   905
val abs_inverse = thm"abs_inverse";
paulson@14387
   906
val abs_triangle_ineq = thm"abs_triangle_ineq";
paulson@14387
   907
val abs_minus_cancel = thm"abs_minus_cancel";
paulson@14387
   908
val abs_minus_add_cancel = thm"abs_minus_add_cancel";
paulson@14387
   909
val abs_interval_iff = thm"abs_interval_iff";
paulson@14387
   910
val abs_le_interval_iff = thm"abs_le_interval_iff";
paulson@14387
   911
val abs_add_one_gt_zero = thm"abs_add_one_gt_zero";
paulson@14387
   912
val abs_le_zero_iff = thm"abs_le_zero_iff";
paulson@14387
   913
val abs_add_one_not_less_self = thm"abs_add_one_not_less_self";
paulson@14387
   914
val abs_sum_triangle_ineq = thm"abs_sum_triangle_ineq";
paulson@14334
   915
paulson@14387
   916
val abs_mult_less = thm"abs_mult_less";
paulson@14334
   917
*}
paulson@10752
   918
paulson@14387
   919
paulson@5588
   920
end