3 uses

     3 uses

     4   ("Tools/numeral.ML")

     4   ("Tools/numeral.ML")

     5   ("Tools/numeral_syntax.ML")

     5   ("Tools/numeral_syntax.ML")

     6   ("Tools/int_arith.ML")

     6   ("Tools/int_arith.ML")

     7 begin

     7 begin

     8 

     9 

     9 fun

    10 fun

    10   intrel :: "(nat \<times> nat) \<Rightarrow> (nat \<times> nat) \<Rightarrow> bool" (infix "\<approx>" 50)

    11   intrel :: "(nat \<times> nat) \<Rightarrow> (nat \<times> nat) \<Rightarrow> bool" (infix "\<approx>" 50)

    11 where

    12 where

    12   "intrel (x, y) (u, v) = (x + v = u + y)"

    13   "intrel (x, y) (u, v) = (x + v = u + y)"