A bstract Computing the exact spectrum of charged massless matter is a crucial step towards
understanding the effective field theory describing F-theory vacua in four dimensions. In this …

We prove an analogon of the the fundamental homomorphism theorem for certain classes of
exact and essentially surjective functors of Abel ian categories Q:A→B. It states that Q is up …

To develop a constructive description of Ext in categories of coherent sheaves over certain
schemes, we establish a binatural isomorphism between the Ext-groups in Serre quotient …