Results 61 to 70 of about 145,190 (272)
A note on global existence for boundary value problems
International Journal of Mathematics and Mathematical Sciences, 1989 Upper and lower solutions are used in establlsning global existence results for certain two–point boundary value problems for y‴=f(x,y,y′,y″) and y(n)=f(x,y,y′,...,y(n−1)).
Chuan J. Chyan, Johnny Henderson
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On 3‐Designs From P G L ( 2 , q ) $PGL(2,q)$
Journal of Combinatorial Designs, EarlyView.ABSTRACT The group P G L ( 2 , q ) $PGL(2,q)$ acts 3‐transitively on the projective line G F ( q ) ∪ { ∞ } $GF(q)\cup \{\infty \}$. Thus, an orbit of its action on the k $k$‐subsets of the projective line is the block set of a 3‐ ( q + 1 , k , λ ) $(q+1,k,\lambda )$ design.
Paul Tricot
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Graphs with 3-Rainbow Index n − 1 and n − 2
Discussiones Mathematicae Graph Theory, 2015 Let G = (V (G),E(G)) be a nontrivial connected graph of order n with an edge-coloring c : E(G) → {1, 2, . . . , q}, q ∈ N, where adjacent edges may be colored the same. A tree T in G is a rainbow tree if no two edges of T receive the same color.
Li Xueliang +3 more
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Coxeter-biCatalan combinatorics [PDF]
Discrete Mathematics & Theoretical Computer Science, 2015 We consider several counting problems related to Coxeter-Catalan combinatorics and conjecture that the problems all have the same answer, which we call the $W$ -biCatalan number. We prove the conjecture in many cases.
Emily Barnard, Nathan Reading
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Combinatorics of embeddings [PDF]
, 2011 We offer the following explanation of the statement of the Kuratowski graph planarity criterion and of 6/7 of the statement of the Robertson-Seymour-Thomas intrinsic linking criterion.
Melikhov, Sergey A.
core
Unimodality Problems in Ehrhart Theory
, 2017 Ehrhart theory is the study of sequences recording the number of integer points in non-negative integral dilates of rational polytopes. For a given lattice polytope, this sequence is encoded in a finite vector called the Ehrhart $h^*$-vector. Ehrhart $h^*
A. Stapledon +45 more
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Historia Mathematica, 1979 AbstractCombinatorics has been rather neglected by historians of mathematics. Yet there are good reasons for studying the origins of the subject, since it is a kind of mathematical subculture, not exactly parallel in its development with the great disciplines of arithmetic, algebra, and geometry.
openaire +3 more sources
Completing Partial k $k$ ‐Star Designs
Journal of Combinatorial Designs, EarlyView.ABSTRACT A k $k$ ‐star is a complete bipartite graph K 1 , k ${K}_{1,k}$ . A partial k $k$ ‐star design of order n $n$ is a pair ( V , A ) $(V,{\mathscr{A}})$ where V $V$ is a set of n $n$ vertices and A ${\mathscr{A}}$ is a set of edge‐disjoint k $k$ ‐stars whose vertex sets are subsets of V $V$ .
Ajani De Vas Gunasekara, Daniel Horsley
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Generalized Rainbow Connection of Graphs and their Complements
Discussiones Mathematicae Graph Theory, 2018 Let G be an edge-colored connected graph. A path P in G is called ℓ-rainbow if each subpath of length at most ℓ + 1 is rainbow. The graph G is called (k, ℓ)-rainbow connected if there is an edge-coloring such that every pair of distinct vertices of G is ...
Li Xueliang +3 more
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A simple recurrence formula for the number of rooted maps on surfaces by edges and genus [PDF]
Discrete Mathematics & Theoretical Computer Science, 2014 We establish a simple recurrence formula for the number $Q_g^n$ of rooted orientable maps counted by edges and genus. The formula is a consequence of the KP equation for the generating function of bipartite maps, coupled with a Tutte equation, and it was
Sean Carrell, Guillaume Chapuy
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