arbboolSyntax.arb : termConstant denoting arbitrary items.
The ML variable boolSyntax.arb is bound to the term
bool$ARB.
boolSyntax.equality, boolSyntax.implication,
boolSyntax.select, boolSyntax.T, boolSyntax.F, boolSyntax.universal,
boolSyntax.existential,
boolSyntax.exists1,
boolSyntax.conjunction,
boolSyntax.disjunction,
boolSyntax.bool_case