Abstract
For a compact Riemann surface X of genus g, we will construct a holomorphic section of the line bundle π1*KXg(g+1)(g+2)/6 $\otimes$ π2*KXg(g+1)(g+2)/6 over X × X whose zero set consists exactly of the points (P,Q) with the cardinalities of the Weierstrass gap sets G(P,Q) greater than the minimal value (g2 + 3g)/2.