“…Thus, according to the general rule [5], the zero loci of b 8,2k are the places (on the base) where a hypermultiplet transforming in 2k of A 2k−1 arises, and that of c 1,0 are where a hypermultiplet in k(2k − 1) appears. In general, a section c i,j or b i,j or whatever with a subscript (i, j) is expressed as a polynomial of degree (i − j)n + 2i in w [45], so we have (8 − 2k)n + 16 hypermultiplets in the 2k representation, and n + 2 hypermultiplets in the k(2k − 1) representation. We will focus on the singularity enhancement to D 2k at the zero loci of c 1,0 since it is this singularity enhancement that its associated conifold singularities and their transitions are closely related to the split/non-split transitions in F-theory.…”