doc-src/TutorialI/Misc/Plus.thy
changeset 48985 5386df44a037
parent 48984 f51d4a302962
child 48986 037d32448e29
equal deleted inserted replaced
48984:f51d4a302962 48985:5386df44a037
     1 (*<*)
       
     2 theory Plus imports Main begin
       
     3 (*>*)
       
     4 
       
     5 text{*\noindent Define the following addition function *}
       
     6 
       
     7 primrec add :: "nat \<Rightarrow> nat \<Rightarrow> nat" where
       
     8 "add m 0 = m" |
       
     9 "add m (Suc n) = add (Suc m) n"
       
    10 
       
    11 text{*\noindent and prove*}
       
    12 (*<*)
       
    13 lemma [simp]: "!m. add m n = m+n"
       
    14 apply(induct_tac n)
       
    15 by(auto)
       
    16 (*>*)
       
    17 lemma "add m n = m+n"
       
    18 (*<*)
       
    19 by(simp)
       
    20 
       
    21 end
       
    22 (*>*)