18 citations · 42 across the 19 of their papers we have counts for
4 papers · 1 filter
The covariant functoriality of graph algebras
Piotr M. Hajac, Mariusz Tobolski
In the standard category of directed graphs, graph morphisms map edges to edges. By allowing graph morphisms to map edges to finite paths (path homomorphisms of graphs), we obtain…
From length-preserving pushouts of graphs to one-surjective pullbacks of graph algebras
Piotr M. Hajac, Mariusz Tobolski
The unions of directed graphs are the simplest examples of pushouts of directed graphs. The conditions under which they contravariantly induce surjective gauge-equivariant pullback…
Graph algebras
Piotr M. Hajac, Mariusz Tobolski
This introduction to graphs and graph algebras provides the optimal bound for the number of all paths of length in a graph with edges and no loops. Our proof relies o…
A graded pullback structure of Leavitt path algebras of trimmable graphs
Piotr M. Hajac, Atabey Kaygun, Mariusz Tobolski
Motivated by recent results in graph C*-algebras concerning an equivariant pushout structure of the Vaksman-Soibelman quantum odd spheres, we introduce a class of graphs called tri…