Non-split singularities and conifold transitions in F-theory

A bstract In F-theory, if a fiber type of an elliptic fibration involves condition that requires exceptional curve to split into two irreducible components, it is called “split” or “non-split” depending on whether globally possible not. the latter case, gauge symmetry reduced non-simply-laced Lie algebra due monodromy. We show this split/non-split transition is, except for special class models, conifold from resolved deformed side, associated with singularities emerging where codimension-one singularity enhanced D 2 k +2 ( ≥ 1) E 7 . also examine how previous proposal origin non-local matter can be actually implemented in our blow-up analysis.