Function: mfisselfdual
Section: modular_forms
C-Name: mfisselfdual
Prototype: lG
Help: mfisselfdual(F): Checks whether the modular forms F is selfdual or not,
 in other words if it is an eigenform of the Fricke involution.
Doc:  Checks whether the modular forms $F$ is selfdual or not, in other words
 if it is an eigenform of the Fricke involution
 \bprog
 ? mf = mfsplit([35,4]);
 ? apply(mfisselfdual, mfbasis(mf))
 %1 = [0, 0, 0, 0, 0, 0]
 ? apply(mfisselfdual, mfeigenbasis(mf))
 %2 = [1, 1, 1]
 @eprog
