Results 31 to 40 of about 514 (184)
NPA Hierarchy for Quantum Isomorphism and Homomorphism Indistinguishability [PDF]
QuantumMančinska and Roberson [FOCS'20] showed that two graphs are quantum isomorphic if and only if they admit the same number of homomorphisms from any planar graph. Atserias et al.
Prem Nigam Kar +3 more
doaj +1 more source
Formulas for the Number of Weak Homomorphisms from Paths to Ladder Graphs and Stacked Prism Graphs
Journal of Mathematics, 2023 Let G and H be graphs. A mapping f from VG to VH is called a weak homomorphism from G to H if fx=fy or fx,fy∈EH whenever x,y∈EG. A ladder graph is the Cartesian product of two paths, where one of the paths has only one edge.
Hatairat Yingtaweesittikul +2 more
doaj +1 more source
Homomorphisms of planar signed graphs to signed projective cubes [PDF]
Discrete Mathematics & Theoretical Computer Science, 2013 We conjecture that every signed graph of unbalanced girth 2g, whose underlying graph is bipartite and planar, admits a homomorphism to the signed projective cube of dimension 2g1.
Reza Naserasr +2 more
doaj +1 more source
Discrete Applied Mathematics, 1996 As the title of this paper shows the two authors deal with homomorphically full graphs. After having given the precise definition of the concept of a homomorphically full graph and the proof of two very interesting properties of homomorphically full graphs the two authors succeed in proving the main result of this paper saying the equivalence of six ...
Richard C. Brewster, Gary MacGillivray
openaire +1 more source
Homomorphisms of Sparse Signed Graphs [PDF]
The Electronic Journal of Combinatorics, 2020 The notion of homomorphism of signed graphs, introduced quite recently, provides better interplay with the notion of minor and is thus of high importance in graph coloring. A newer, but equivalent, definition of homomorphisms of signed graphs, proposed jointly by the second and third authors of this paper and Thomas Zaslavsky, leads to a basic no ...
Charpentier, Clément +2 more
openaire +1 more source
A digraph equation for homomorphic images
International Journal of Mathematics and Mathematical Sciences, 1986 The definitions of a homomorphism and a contraction of a graph are generalized to digraphs. Solutions are given to the graph equation ϕ(D)¯=θϕ(D¯).
Robert D. Girse, Richard A. Gillman
doaj +1 more source
Discrete Dynamics in Nature and Society, 2021 People worldwide communicate online and create a great amount of data on social media. The understanding of such large-scale data generated on social media and uncovering patterns from social relationship has received much attention from academics and ...
Zhao Huang, Liu Yuan
doaj +1 more source
Homomorphisms and related contractions of graphs
International Journal of Mathematics and Mathematical Sciences, 1988 For every homomorphism ϕ of a graph G there exists a contraction θϕ on G¯, the complement of G. Here we study the graph equation ϕ(G)=θϕ(G¯). In the course of our work we show that Hadwiger's Conjecture is true for every self-complementary graph.
Robert D. Girse, Richard A. Gillman
doaj +1 more source
Homomorphisms of complete n-partite graphs
International Journal of Mathematics and Mathematical Sciences, 1986 It is shown that for every homomorphism ϕ of a graph G there exists a contraction θϕ on G¯, the complement of G, such that ϕ(G)¯=θϕ(G¯) if and only if G is a complete n-partite graph.
Robert D. Girse
doaj +1 more source
CONTINUITY OF UNIVERSALLY MEASURABLE HOMOMORPHISMS
Forum of Mathematics, Pi, 2019 Answering a longstanding problem originating in Christensen’s seminal work on Haar null sets [Math. Scand. 28 (1971), 124–128; Israel J. Math. 13 (1972), 255–260; Topology and Borel Structure.
CHRISTIAN ROSENDAL
doaj +1 more source