Elimination of fully-functorial style.
Type tactic changed to a type abbrevation (from a datatype).
Constructor tactic and function apply deleted.
Arith = FOL +
classes arith < term
consts "0" :: "'a::arith" ("0")
"1" :: "'a::arith" ("1")
"+" :: "['a::arith,'a] => 'a" (infixl 60)
end