Resultants and Gr\"obner bases are crucial tools in studying polynomial
elimination theory. We investigate relations between the variety of the
resultant of two polynomials and the variety of the ideal they generate. Then
we focus on the bivariate case, in which the elimination ideal is principal. We
study - by means of elementary tools - the difference between the multiplicity
of the factors of the generator of the elimination ideal and the multiplicity
of the factors of the resultant.Comment: 7 page