Defines ZF theory sections (inductive, datatype) at the start/
Moved theory section code here from Inductive.ML and
Datatype.ML
Gate = FOL +
consts nand,xor :: "[o,o] => o"
rules nand_def "nand(P,Q) == ~(P & Q)"
xor_def "xor(P,Q) == P & ~Q | ~P & Q"
end