On curves with high multiplicity on $\mathbb{P}(a,b,c)$ for $\min (a,b,c)\le 4$

Abstract

On a weighted projective surface $\mathbb{P}(a,b,c)$ with $\min (a,b,c)\le 4$, we compute lower bounds for the {\em effective threshold} of an ample divisor, in other words, the highest multiplicity a section of the divisor can have at a specified point. We expect that these bounds are close to being sharp. This translates into finding divisor classes on the blowup of $\mathbb{P}(a,b,c)$ that generate a cone contained in, and probably close to, the effective cone.