-- added combinator reduction axioms (typed and untyped) for HOL goals.
-- combined make_nnf functions for HOL and FOL goals.
-- hypothesis of goals are now also skolemized by inference.
Arith = FOL +
classes arith < term
consts "0" :: "'a::arith" ("0")
"1" :: "'a::arith" ("1")
"+" :: "['a::arith,'a] => 'a" (infixl 60)
end