2 papers
math.RA2026
Relation morphisms of directed graphs
Gilles G. de Castro, Francesco D'Andrea, Piotr M. Hajac
Associating graph algebras to directed graphs leads to both covariant and contravariant functors from suitable categories of graphs to the category k-Alg of algebras and algebra ho…
math.KT2026
Milnor meets Hopf and Toeplitz at the K-theory of quantum projective planes
Francesco D'Andrea, Piotr M. Hajac, Tomasz Maszczyk +1
We explore applications of the celebrated construction of the Milnor connecting homomorphism from the odd to the even K-groups in the context of Hopf--Galois theory. For a finitely…