IsRat( obj )
IsRat
returns true
if obj, which can be an arbitrary object, is a
rational and false
otherwise. Integers are rationals with denominator
1, thus IsRat
returns true
for integers. IsRat
will signal an
error if obj is an unbound variable or a procedure call.
gap> IsRat( 2/3 ); true gap> IsRat( 17/-13 ); true gap> IsRat( 11 ); true gap> IsRat( IsRat ); false # 'IsRat' is a function, not a rational
GAP 3.4.4