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doc-src/Tutorial/Recdef/ack
author wenzelm
Thu, 04 Oct 2001 15:20:40 +0200
changeset 11670 59f79df42d1f
parent 9255 2ceb11a2e190
permissions -rw-r--r--
proof by cases and induction on types and sets (used to be specific for HOL);

consts ack :: "nat*nat => nat"
recdef ack "measure(%m. m) <*lex*> measure(%n. n)"
  "ack(0,n)         = Suc n"
  "ack(Suc m,0)     = ack(m, 1)"
  "ack(Suc m,Suc n) = ack(m,ack(Suc m,n))"
isabelle