Abstract We explore the combinatorial properties of a particular type of extension monoid product of preinjective Kronecker modules. The considered extension monoid product plays an important role in… Expand

Abstract We derive a cancellation theorem for degenerations of modules that says in particular, that projective or injective common direct summands can always be neglected. Combining the cancellation… Expand

The possible Kronecker invariants of a matrix pencil with a prescribed sub pencil, when the prescribed subpencil has only column (row) minimal indices as Kr one-size-fits-all indices is described.Expand

A monoid structure on families of representations of a quiver is introduced by taking extensions of representations in families, that is, subvarieties of the varieties of representations. The study… Expand

This is the first of a series of papers dealing with the representation theory of artin algebras, where by an artin algebra we mean an artin ring having the property that its center is an artin ring… Expand

Integral quadratic forms.- Quivers, module categories, subspace categories (Notation, results, some proofs).- Construction of stable separating tubular families.- Tilting functors and tubular… Expand