The -labeling on total graphs of complete multipartite graphs.
The L²-invariants and Morse numbers
We study the homotopy invariants of free cochain complexes and Hilbert complexes. These invariants are applied to calculation of exact values of Morse numbers of smooth manifolds.
The Lagrange inversion formula and divisibility properties.
The Laplacian permanental polynomial for trees
The Laplacian spectral radius of graphs
The Laplacian spectral radius of a graph is the largest eigenvalue of the associated Laplacian matrix. In this paper, we improve Shi's upper bound for the Laplacian spectral radius of irregular graphs and present some new bounds for the Laplacian spectral radius of some classes of graphs.
The Laplacian spectrum of some digraphs obtained from the wheel
The problem of distinguishing, in terms of graph topology, digraphs with real and partially non-real Laplacian spectra is important for applications. Motivated by the question posed in [R. Agaev, P. Chebotarev, Which digraphs with rings structure are essentially cyclic?, Adv. in Appl. Math. 45 (2010), 232-251], in this paper we completely list the Laplacian eigenvalues of some digraphs obtained from the wheel digraph by deleting some arcs.
The Laplacian spread of graphs
The Laplacian spread of a graph is defined as the difference between the largest and second smallest eigenvalues of the Laplacian matrix of the graph. In this paper, bounds are obtained for the Laplacian spread of graphs. By the Laplacian spread, several upper bounds of the Nordhaus-Gaddum type of Laplacian eigenvalues are improved. Some operations on Laplacian spread are presented. Connected -cyclic graphs with vertices and Laplacian spread are discussed.
The Laplacian spread of tricyclic graphs.
The largest component in an inhomogeneous random intersection graph with clustering.
The largest intersection lattice of a discriminantal arrangement.
The Largest Subdeterminant of a Matrix
The last digit of and .
The lattice of all subtrees of a tree
The lattice of integral flows and the lattice of integral cuts on a finite graph
The lattice of threshold graphs.
The leafage of a chordal graph
The leafage l(G) of a chordal graph G is the minimum number of leaves of a tree in which G has an intersection representation by subtrees. We obtain upper and lower bounds on l(G) and compute it on special classes. The maximum of l(G) on n-vertex graphs is n - lg n - 1/2 lg lg n + O(1). The proper leafage l*(G) is the minimum number of leaves when no subtree may contain another; we obtain upper and lower bounds on l*(G). Leafage equals proper leafage on claw-free chordal graphs. We use asteroidal...
The least connected non-vertex-transitive graph with constant neighbourhoods
The Least Eigenvalue of Graphs whose Complements Are Uni- cyclic
A graph in a certain graph class is called minimizing if the least eigenvalue of its adjacency matrix attains the minimum among all graphs in that class. Bell et al. have identified a subclass within the connected graphs of order n and size m in which minimizing graphs belong (the complements of such graphs are either disconnected or contain a clique of size n/2 ). In this paper we discuss the minimizing graphs of a special class of graphs of order n whose complements are connected and contains...
The lifted root number conjecture for fields of prime degree over the rationals: an approach via trees and Euler systems
The so-called Lifted Root Number Conjecture is a strengthening of Chinburg’s - conjecture for Galois extensions of number fields. It is certainly more difficult than the -localization. Following the lead of Ritter and Weiss, we prove the Lifted Root Number Conjecture for the case that and the degree of is an odd prime, with another small restriction on ramification. The very explicit calculations with cyclotomic units use trees and some classical combinatorics for bookkeeping. An important...
The linear arboricity of -regular graphs