existentialboolSyntax.existential : termConstant denoting existential quantification.
The ML variable boolSyntax.existential is bound to the
term bool$?.
boolSyntax.equality, boolSyntax.implication,
boolSyntax.select, boolSyntax.T, boolSyntax.F, boolSyntax.universal,
boolSyntax.exists1,
boolSyntax.conjunction,
boolSyntax.disjunction,
boolSyntax.negation,
boolSyntax.conditional,
boolSyntax.bool_case,
boolSyntax.let_tm, boolSyntax.arb