Results 141 to 150 of about 2,319,892 (295)
Exact Values and Bounds on Covering Schemes of Strength Two
Journal of Combinatorial Designs, EarlyView.ABSTRACT In this work, we investigate covering schemes of strength 2 over finite abelian groups, establishing new lower and upper bounds and evaluating new exact values. A main result is a new general lower bound that improves the trivial one and achieves optimality for the binary case. We also develop a recursive relation based on subsets of the group
André G. Castoldi +4 more
wiley +1 more source
Immunizing Conic Quadratic Optimization Problems Against Implementation Errors [PDF]
We show that the robust counterpart of a convex quadratic constraint with ellipsoidal implementation error is equivalent to a system of conic quadratic constraints.
Ben-Tal, A., Hertog, D. den
core
Catalan Bounds for Symmetric Strength‐Two Orthogonal Arrays
Journal of Combinatorial Designs, EarlyView.ABSTRACT A Hamming shell construction is a two‐level array obtained by taking every binary vector of a given Hamming weight a prescribed number of times, for each weight in turn. Such arrays are invariant under all permutations of the factors, and they are strength‐two orthogonal arrays exactly when the multiplicities satisfy three linear constraints ...
Ruwan C. Karunanayaka
wiley +1 more source
Journal of Graph Theory, EarlyView.ABSTRACT In this paper we define a degree for ends of infinite digraphs. The well‐definedness of our definition in particular resolves a problem by Zuther. Furthermore, we extend our notion of end degree to also respect, among others, the vertices dominating the end, which we denote as combined end degree.
Matthias Hamann, Karl Heuer
wiley +1 more source
, 2008 The Kalman-Yakubovich-Popov (KYP) lemma is a useful tool in control and signal processing that allows an important family of computationally intractable semi-infinite programs in the entire frequency range to be characterized by computationally tractable semidefinite programs.
openaire +2 more sources
, 2016 The classical snake lemma produces a six terms exact sequence starting from a commutative square with one of the edge being a regular epimorphism. We establish a new diagram lemma, that we call snail lemma, removing such a condition.
Vitale, Enrico
core
Journal of Graph Theory, EarlyView.ABSTRACT In an effort to understand the complexity of the maximum independent set problem, Chvátal introduced t‐perfect graphs. While a full characterization of this class remains open, important progress has been made for claw‐free graphs [Bruhn and Stein, Math. Program. 2012] and P 5 ${P}_{5}$‐free graphs [Bruhn and Fuchs, SIAM J. Discrete Math. 2017]
Yixin Cao, Shenghua Wang
wiley +1 more source
Flexible List Coloring of Graphs With Maximum Average Degree Less Than 3
Journal of Graph Theory, EarlyView.ABSTRACT In the flexible list coloring problem, we consider a graph G $G$ and a color list assignment L $L$ on G $G$, as well as a subset U ⊆ V ( G ) $U\subseteq V(G)$ for which each u ∈ U $u\in U$ has a preferred color p ( u ) ∈ L ( u ) $p(u)\in L(u)$. Our goal is to find a proper L $L$‐coloring ϕ $\phi $ of G $G$ such that ϕ ( u ) = p ( u ) $\phi (u)=
Richard Bi, Peter Bradshaw
wiley +1 more source
International Journal of Robust and Nonlinear Control, EarlyView., 2023 Abstract We propose a hierarchical energy management scheme for aggregating Distributed Energy Resources (DERs) for grid flexibility services. To prevent a direct participation of numerous prosumers in the wholesale electricity market, aggregators, as self‐interest agents in our scheme, incentivize prosumers to provide flexibility. We firstly model the
Xiupeng Chen +3 more
wiley +1 more source
Sparse Graphs With Local Covering Conditions on Edges
Journal of Graph Theory, EarlyView.ABSTRACT In 1988, Erdős suggested the question of minimizing the number of edges in a connected n $n$‐vertex graph where every edge is contained in a triangle. Shortly after, Catlin, Grossman, Hobbs, and Lai resolved this in a stronger form. In this paper, we study a natural generalization of the question of Erdős in which we replace “triangle” with ...
Debsoumya Chakraborti +3 more
wiley +1 more source