18 jun 2015 -- 11:30
Sala Seminari, DM, Pisa
A topological foundation-interpretation is provided for the the algebraic notion of string junctions. This new approach permits the analysis of elliptic fibrations using deformations rather than resolutions. As a result we obtain the associated gauge algebras, their representation, Dynkin diagrams, root systems, etc., first for complex codimension one singularities and then for higher codimension strata in the singular set, for example corresponding to the G2 gauge group or for the "III-IV-I" collision (with A. Grassi, J. Halverson and W. Taylor).