Improving dense packings of equal disks in a square.
Improving some bounds for dominating Cartesian products
The study of domination in Cartesian products has received its main motivation from attempts to settle a conjecture made by V.G. Vizing in 1968. He conjectured that γ(G)γ(H) is a lower bound for the domination number of the Cartesian product of any two graphs G and H. Most of the progress on settling this conjecture has been limited to verifying the conjectured lower bound if one of the graphs has a certain structural property. In addition, a number of authors have established bounds for dominating...
In the Square of Graphs, Hamiltonicity and Pancyclicity, Hamiltonian Connectedness and Panconnectedness Are Equivalent Concepts.
Incidence complexes and r-connectedness
Incomplete idempotent Schröder quasigroups and related packing designs.
Increasing integer sequences and Goldbach's conjecture
Increasing integer sequences include many instances of interesting sequences and combinatorial structures, ranging from tournaments to addition chains, from permutations to sequences having the Goldbach property that any integer greater than 1 can be obtained as the sum of two elements in the sequence. The paper introduces and compares several of these classes of sequences, discussing recurrence relations, enumerative problems and questions concerning shortest sequences.
Increasing subsequences and the classical groups.
Increasing trees and Kontsevich cycles.
Indecomposable tilings of the integers with exponentially long periods.
In-degree sequence in a general model of a random digraph
A general model of a random digraph D(n,P) is considered. Based on a precise estimate of the asymptotic behaviour of the distribution function of the binomial law, a problem of the distribution of extreme in-degrees of D(n,P) is discussed.
Independence complexes and edge covering complexes via Alexander duality.
Independence complexes of stable Kneser graphs.
Independence number and degree bounded spanning tree.
Independence number and disjoint theta graphs.
Independence number and minimum degree for the existence of -critical graphs.
Independence number of 2-factor-plus-triangles graphs.
Independence structures in the geometry of orders.
Independent Collections of Translates of Boxes and a Conjecture due to Grünbaum.
Independent cycles and paths in bipartite balanced graphs
Bipartite graphs G = (L,R;E) and H = (L’,R’;E’) are bi-placeabe if there is a bijection f:L∪R→ L’∪R’ such that f(L) = L’ and f(u)f(v) ∉ E’ for every edge uv ∈ E. We prove that if G and H are two bipartite balanced graphs of order |G| = |H| = 2p ≥ 4 such that the sizes of G and H satisfy ||G|| ≤ 2p-3 and ||H|| ≤ 2p-2, and the maximum degree of H is at most 2, then G and H are bi-placeable, unless G and H is one of easily recognizable couples of graphs. This result implies easily that for integers...
Independent Detour Transversals in 3-Deficient Digraphs
In 1982 Laborde, Payan and Xuong [Independent sets and longest directed paths in digraphs, in: Graphs and other combinatorial topics (Prague, 1982) 173-177 (Teubner-Texte Math., 59 1983)] conjectured that every digraph has an independent detour transversal (IDT), i.e. an independent set which intersects every longest path. Havet [Stable set meeting every longest path, Discrete Math. 289 (2004) 169-173] showed that the conjecture holds for digraphs with independence number two. A digraph is p-deficient...