A homomorphism from an oriented graph G to an oriented graph H is an arc-preserving mapping f from V(G) to V(H), that is f(x)f(y) is an arc in H whenever xy is an arc in G. The or...
We use two fourth order geometric partial differential equations to efficiently solve several surface modelling problems, including the surface blending, the N-sided hole fillin...
We apply language theory to compare the expressive power of models that extend Petri nets with features like colored tokens and/or whole place operations. Specifically, we conside...
We investigate the complexity of various combinatorial theorems about linear and partial orders, from the points of view of computability theory and reverse mathematics. We focus ...
The concept of a partial derangement is introduced and a versatile representation of partial derangements is proposed with permutations and derangements as special cases. The repre...