GF(Ring) -- make a finite field from a ring

GF R -- make a Galois field from a quotient ring R which happens to be isomorphic to a finite field.

i1 : k = GF(ZZ/2[t]/(t^3+t+1)) o1 = k o1 : GaloisField

i2 : t+t^2 2 o2 = t + t o2 : k