Results 101 to 110 of about 6,526 (216)

On Strongly and Robustly Critical Graphs

Journal of Graph Theory, Volume 112, Issue 4, Page 469-483, August 2026.
ABSTRACT In extremal combinatorics, it is common to focus on structures that are minimal with respect to a certain property. In particular, critical and list‐critical graphs occupy a prominent place in graph coloring theory. Stiebitz, Tuza, and Voigt introduced strongly critical graphs, i.e., graphs that are k‐critical yet L‐colorable with respect to ...
Anton Bernshteyn, Hemanshu Kaul, Jeffrey A. Mudrock, Gunjan Sharma   +3 more
wiley   +1 more source

Weak, Strong and Mixed Extensions of Relations to Spaces of Ultrafilters

Mathematical Logic Quarterly, Volume 72, Issue 3, August 2026.
ABSTRACT The use of nonstandard methods to characterize properties of weak, strong and mixed extensions of congruences to ultrafilters has been the main topic of several recent papers, focused mostly on congruences and divisions. We show that similar methods can be used to extend these characterizations to arbitrary relations and their interplay.
Leonardo Raffaello Maximilian Gasparro, Lorenzo Luperi Baglini   +1 more
wiley   +1 more source

On Matrix‐Based Cryptography Using Matrix Norm and Special Integer Sequences

Mathematische Nachrichten, Volume 299, Issue 8, Page 2087-2102, August 2026.
ABSTRACT In this paper, a novel matrix‐based encryption approach based on the Affine Hill cipher is presented. The key matrix is constructed using the Narayana integer sequence, and the Frobenius norm of the key matrix is used as a scaling factor in the key construction.
Melih Göcen, Sümeyye Hacer Büyükakyol   +1 more
wiley   +1 more source

Random Friend Trees

Random Structures &Algorithms, Volume 69, Issue 1, August 2026.
ABSTRACT We study a random recursive tree model featuring complete redirection called the random friend tree and introduced by Saramäki and Kaski (2004). Vertices are attached sequentially, one by one, by selecting an existing target vertex and connecting to one of its neighbours (or friends), chosen uniformly at random.
Louigi Addario‐Berry, Simon Briend, Luc Devroye, Serte Donderwinkel, Céline Kerriou, Gábor Lugosi   +5 more
wiley   +1 more source

Asymmetric Results About Graph Homomorphisms

Random Structures &Algorithms, Volume 69, Issue 1, August 2026.
ABSTRACT Many important results in extremal graph theory can be roughly summarized as “if a triangle‐free graph G$$ G $$ has certain properties, then it has a homomorphism to a triangle‐free graph Γ$$ \Gamma $$ of bounded size.” For example, bounds on homomorphism thresholds give such a statement if G$$ G $$ has sufficiently high minimum degree, and ...
Lior Gishboliner, Eoin Hurley, Yuval Wigderson   +2 more
wiley   +1 more source

RAINBOW VERTEX CONNECTION NUMBER OF BULL GRAPH, NET GRAPH, TRIANGULAR LADDER GRAPH, AND COMPOSITION GRAPH (P_n [P_1 ])

Barekeng
The rainbow connection was first introduced by Chartrand in 2006 and then in 2009 Krivelevich and Yuster first time introduced the rainbow vertex connection. Let graph be a connected graph.
Muhammad Ilham Nurfaizi Annadhifi, Robiatul Adawiyah, Dafik Dafik, I Nengah Suparta   +3 more
doaj   +1 more source

The combinatorics of Motzkin polyominoes

Discrete Applied Mathematics
A word $w=w_1\cdots w_n$ over the set of positive integers is a Motzkin word whenever $w_1=\texttt{1}$, $1\leq w_k\leq w_{k-1}+1$, and $w_{k-1}\neq w_{k}$ for $k=2, \dots, n$. It can be associated to a $n$-column Motzkin polyomino whose $i$-th column contains $w_i$ cells, and all columns are bottom-justified.
Baril, Jean-Luc, Kirgizov, Sergey, Ramírez, José, Villamizar, Diego   +3 more
openaire   +3 more sources

Resident Fitness Computation in Linear Time and Other Algorithmic Aspects of Interacting Trajectories

Random Structures &Algorithms, Volume 69, Issue 1, August 2026.
ABSTRACT Systems of interacting trajectories were recently studied in Hermann et al. (2025). Such a system of [0,1]$$ \left[0,1\right] $$‐valued piecewise linear trajectories arises as a scaling limit of the system of logarithmic subpopulation sizes in a population‐genetic model (more precisely, a Moran model) with mutation and selection. By definition,
Katalin Friedl, Viktória Nemkin, András Tóbiás   +2 more
wiley   +1 more source

Representation Functions With Prescribed Rates of Growth

Random Structures &Algorithms, Volume 69, Issue 1, August 2026.
ABSTRACT Fix an integer h≥2$$ h\ge 2 $$, and let b1,…,bh$$ {b}_1,\dots, {b}_h $$ be (not necessarily distinct) positive integers with gcd(b1,…,bh)=1$$ \gcd \left({b}_1,\dots, {b}_h\right)=1 $$. For any subset A⊆ℕ$$ A\subseteq \mathbb{N} $$, let rA(n)$$ {r}_A(n) $$ denote the number of solutions (k1,…,kh)∈Ah$$ \left({k}_1,\dots, {k}_h\right)\in {A}^h $$
Christian Táfula
wiley   +1 more source

The VC‐Dimension of Random Subsets of Finite Groups

Random Structures &Algorithms, Volume 69, Issue 1, August 2026.
ABSTRACT For a random subset of a finite group G$$ G $$ of cardinality N$$ N $$, we consider the VC‐dimension of the family of its translates (equivalently the VC‐dimension of a random Cayley graph) and prove a law of large numbers as N→∞$$ N\to \infty $$. This answers a question of McDonald–Sahay–Wyman.
Brad Rodgers, Anurag Sahay
wiley   +1 more source