  This paper, a continuation of [3], involves a closer study of polynomials of
supertropical semirings and their version of tropical geometry in which we
introduce the concept of relatively prime polynomials and resultants, with the
aid of some topology. Polynomials in one indeterminant are seen to be
relatively prime iff they do not have a common tangible root, iff their
resultant is tangible. The Frobenius property yields a morphism of
supertropical varieties; this leads to a supertropical version of B\'ezout's
theorem. Also, a supertropical variant of factorization is introduced which
yields a more comprehensive version of Hilbert's Nullstellensatz than the one
given in [3].
