A graph is s-regular if its automorphism group acts regularly on the set of its s-arcs. In this paper, the s-regular elementary abelian coverings of the complete bipartite graph K3,3 and the s-regular cyclic or elementary abelian coverings of the complete graph K4 for each s 1 are classified when the fibrepreserving automorphism groups act arc-transitively. A new infinite family of cubic 1-regu...

in order to study of the effect of nitrogen source, operation method and weed control methods on weed biomass, yield and yield components of corn (zea mays l.) an experiment was carried out as split plot factorial based on randomized complete block design (rcbd) with four replications in shahrood university of technology. the treatments included weed control methods at four levels (hand weeding...

in this paper, we investigate various kinds of extensions of twin-good rings. moreover, we prove that every element of an abelian neat ring r is twin-good if and only if r has no factor ring isomorphic to z2  or z3. the main result of [24] states some conditions that any right self-injective ring r is twin-good. we extend this result to any regular baer ring r by proving that every element of a...

Let M be a submonoid of the free monoid A∗, and let X ⊆ M be a variable length code (for short a code). X is weakly M-complete if any word in M is a factor of some word in X∗ [J. Néraud, C. Selmi, Free monoid theory: maximality and completeness in arbitrary submonoids, Internat. J. Algorithms Comput. 13(5) (2003) 507–516]. Given a code X ⊆ M , we are interested in the construction of a weakly M...

This paper discusses a learning algorithm for regular sets in the model of learning in the limit from complete data (i.e., positive and negative data). We rst present some characterization results for regular sets in the rough set theoretic framework. More speci cally, it is shown that any regular set is R-de nable for some kinds of equivalence relations R of nite index. We then show that regul...

A complete classification is given of vertex primitive and vertex bi-primitive s-arc regular graphs with s ≥ 3. In particular, it is shown that the Petersen graph and Coxeter graph are the only vertex primitive 3-arc regular graphs, and that vertex bi-primitive 3-arc regular graphs consist of the complete bipartite graph K3,3, the standard double covers of the Petersen graph and Coxeter graph, ...

We prove that if a graph H has the same Tutte polynomial as the line graph of a d-regular, d-edge-connected graph, then H is the line graph of a d-regular graph. Using this result we prove that the line graph of a regular complete t-partite graph is uniquely determined by its Tutte polynomial. We prove the same result for the line graph of any complete bipartite graph.