S-Polynomial

For two polynomials f and g with leading terms lt(f) and lt(g), the S-polynomial is the combination S(f,g) = (lcm(lt(f),lt(g))/lt(f)) * f - (lcm(lt(f),lt(g))/lt(g)) * g that cancels the leading terms; it measures the compatibility of leading terms in Gröbner-basis computations.