src/HOL/RealDef.thy
changeset 40810 142f890ceef6
parent 38857 97775f3e8722
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40809:86dff9dfd806 40810:142f890ceef6
    12 begin
    12 begin
    13 
    13 
    14 text {*
    14 text {*
    15   This theory contains a formalization of the real numbers as
    15   This theory contains a formalization of the real numbers as
    16   equivalence classes of Cauchy sequences of rationals.  See
    16   equivalence classes of Cauchy sequences of rationals.  See
    17   \url{HOL/ex/Dedekind_Real.thy} for an alternative construction
    17   @{file "~~/src/HOL/ex/Dedekind_Real.thy"} for an alternative
    18   using Dedekind cuts.
    18   construction using Dedekind cuts.
    19 *}
    19 *}
    20 
    20 
    21 subsection {* Preliminary lemmas *}
    21 subsection {* Preliminary lemmas *}
    22 
    22 
    23 lemma add_diff_add:
    23 lemma add_diff_add: