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Showing 209 results for "romania)" in Mathematics
Mathematics Preprint PDF DOI

Upper bounds for double Roman domination and $[k]$-Roman domination of cylindrical graphs $C_m \Box P_n$

Simon Brezovnik, Janez Zerovnik ยท 2026

Roman-type domination parameters form an important class of graph invariants that model protection and resource allocation problems on networks. Among them, $[k]$-Roman domination provides a unified fโ€ฆ

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Bounds for (strong) Roman $k$-dominations

Fahimeh Khosh-Ahang Ghasr ยท 2026

Motivated by resource defense models in networks, such as protecting territories with varying legion strengths, let $k \geq 2$ be an integer. Roman $k$-domination and strong Roman $k$-domination generโ€ฆ

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Further results on \([k]\)-Roman domination on cylindrical grids \(C_m \Box P_n\)

Simon Brezovnik, Janez Zerovnik ยท 2026

In this paper, we study the $[k]$-Roman domination number of cylindrical graphs $C_m \Box P_n$. Our analysis begins with a general lower bound based on local neighborhood constraints, showing that $\gโ€ฆ

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Double Italian domination in trees

Weiping Shang, Shanshan Zhang ยท 2026

Let $G$ be a graph with vertex set $V=V(G)$. A double Roman dominating function on a graph $G$ is a function $f : V \to \{0,1,2,3\}$ satisfying the conditions that if $f(v) = 0$, then vertex $v$ must โ€ฆ

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On the Green-Tao theorem for sparse sets

Joni Teravainen, Mengdi Wang ยท 2026

We establish the following quantitative form of the Green--Tao theorem: if a set $\mathcal{A}$ of relative density $\delta$ within the primes up to $N$ contains no nontrivial arithmetic progressions oโ€ฆ

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$[k]$-Roman domination on cylindrical grids $C_m \Box P_n$

Simon Brezovnik, Janez Zerovnik ยท 2026

Roman domination and its higher-order extensions have attracted considerable attention due to their natural interpretation in terms of defensive resource allocation on networks. The recently introduceโ€ฆ

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Parameterized complexity of $r$-Hop, $r$-Step, and $r$-Hop Roman Domination

Sandip Das, Sweta Das, Sk Samim Islam ยท 2026

The \textsc{Dominating Set} problem is a classical and extensively studied topic in graph theory and theoretical computer science. In this paper, we examine the algorithmic complexity of several well-โ€ฆ

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Total Roman bondage number of a graph

Fahimeh Khosh-Ahang Ghasr, Sakineh Nazari-Moghaddam ยท 2026

A total Roman dominating function (TRDF) on a graph $G$ with no isolated vertices is a function $f:V(G)\to\{0,1,2\}$ such that every vertex $v$ with $f(v)=0$ has a neighbor assigned $2$, and the subgrโ€ฆ

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A dual view of Roman Domination: The 2-limited packing problem

Oliver Bachtler, Sven O. Krumke, Helena Wei{ss} ยท 2026

We consider the 2-limited packing problem: for a graph $G=(V,E)$ one seeks to find a maximum cardinality subset $B\subseteq V$, such that, for all $v\in V$, the closed neighbourhood of $v$ contains atโ€ฆ

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On the complexity of global Roman domination problem in graphs

Sangam Balchandar Reddy, Arun Kumar Das, Anjeneya Swami Kare, I. Vinod Reddy ยท 2026

A Roman dominating function of a graph $G=(V,E)$ is a labeling $f: V \rightarrow{} \{0 ,1, 2\}$ such that for each vertex $u \in V$ with $f(u) = 0$, there exists a vertex $v \in N(u)$ with $f(v) =2$. โ€ฆ

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Mathematics in the liturgical books of the Catholic Church: phases of the ecclesiastical moon

Henryk Fuks ยท 2026

We use contemporary mathematical notation to describe the method for determining the age of the ecclesiastical moon as mandated by pope Gregory XIII and elaborated in the book of Christopher Clavius \โ€ฆ

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Roman domination in weighted graphs

Martin Cera, Pedro Garcia-Vazquez, Juan Carlos Valenzuela-Tripodoro ยท 2025

A Roman dominating function for a (non-weighted) graph $G=(V,E)$, is a function $f:V\rightarrow \{0,1,2\}$ such that every vertex $u\in V$ with $f(u)=0$ has at least {one} neighbor $v\in V$ such that โ€ฆ

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Hawksmoor's Ceiling, Mercator's Projection and the Roman Pantheon

John Cardy ยท 2025

The ceiling of the Buttery in All Souls College, Oxford, designed by the English Baroque architect Nicholas Hawksmoor, has a vaulted form on an oval base. It is coffered with an array of approximatelyโ€ฆ

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Enumeration With Nice Roman Domination Properties

Kevin Mann ยท 2025

Although Extension Perfect Roman Domination is NP-complete, all minimal (with respect to the pointwise order) perfect Roman dominating functions can be enumerated with polynomial delay. This algorithmโ€ฆ

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Roman $\{2\}$-domination on Graphs with "few" 4-paths

Lara Fernandez, Valeria Leoni ยท 2025

Given a graph $G$ with vertex set $V$, $f : V \rightarrow \{0, 1, 2\}$ is a \emph{Roman $\{2\}$-dominating function} (or \emph{italian dominating function}) of $G$ if for every vertex $v\in V$ with $fโ€ฆ

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Optimal bounds for sums of bounded arithmetic functions

Andres Chirre, Harald Andres Helfgott ยท 2025

Let $A(s) = \sum_n a_n n^{-s}$ be a Dirichlet series with meromorphic continuation. Say we are given information on the poles of $A(s)$ with $|\Im s| \leq T$ for some large constant $T$. What is the bโ€ฆ

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On $\{k\}$-Roman graphs: complexity of recognition and the case of split graphs

Kenny Bester Storgel, Nina Chiarelli, Lara Fernandez, J. Pascal Gollin, Claire Hilaire, Valeria Leoni, Martin Milanic ยท 2025

For a positive integer $k$, a $\{k\}$-Roman dominating function of a graph $G = (V,E)$ is a function $f\colon V \rightarrow \{0,1,\ldots,k\}$ satisfying $f (N(v)) \geq k$ for each vertex $v\in V$ withโ€ฆ

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Revisiting the Nandakumar-Ramana Rao Conjecture

Surojit Ghosh, Ankit Kumar ยท 2025

We reprove the generalized Nandakumar-Ramana Rao conjecture for the prime case using representation ring-graded Bredon cohomology. Our approach relies solely on the $RO(C_p)$-graded cohomology of confโ€ฆ

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A combinatorial approach to Ramana's exact dual for semidefinite programming

Gabor Pataki ยท 2025

Thirty years ago, in a seminal paper Ramana derived an exact dual for Semidefinite Programming (SDP). Ramana's dual has the following remarkable features: i) it is an explicit, polynomial size semidefโ€ฆ

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Representations of the Chekanov-Eliashberg algebra from closed exact Lagrangians I

Baptiste Chantraine, Georgios Dimitroglou Rizell, Paolo Ghiggini ยท 2025

This is the first of a series of two articles aiming at relating the compact Fukaya category of a Weinstein manifold to the derived category of finite dimensional representations of the Chekanov-Eliasโ€ฆ

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