EJC
2016
8 years 4 months ago
2016
Let C(n) denote the maximum number of induced copies of C5 in graphs on n vertices. For n large enough, we show that C(n) = a · b · c · d · e + C(a) + C(b) + C(c) + C(d) + C(e...
EJC
2016
8 years 4 months ago
2016
EJC
2016
8 years 4 months ago
2016
The maximum drop size of a permutation π of [n] = {1, 2, . . . , n} is defined to be the maximum value of i − π(i). Chung, Claesson, Dukes and Graham found polynomials Pk(x) ...
EJC
2016
8 years 4 months ago
2016
A finite word is u is said to be bordered if u has a proper prefix which is also a suffix of u, and unbordered otherwise. Ehrenfeucht and Silberger proved that an infinite word...
EJC
2016
8 years 4 months ago
2016
We continue to explore cyclotomic factors in the descent set polynomial Qn(t), which was introduced by Chebikin, Ehrenborg, Pylyavskyy and Readdy. We obtain large classes of facto...
EJC
2016
8 years 4 months ago
2016
We study “positive” graphs that have a nonnegative homomorphism number into every edge-weighted graph (where the edgeweights may be negative). We conjecture that all positive ...
EJC
2016
8 years 4 months ago
2016
The well known dichotomy conjecture of Feder and Vardi states that for every family Γ of constraints CSP(Γ) is either polynomially solvable or NP-hard. Bulatov and Jeavons reform...
EJC
2016
8 years 4 months ago
2016
Abstract. Building on recent results regarding symmetric probabilistic constructions of countable structures, we provide a method for constructing probability measures, concentrate...
EJC
2016
8 years 4 months ago
2016
We give a survey of some general results on graph limits associated to hereditary classes of graphs. As examples, we consider some classes defined by forbidden subgraphs and some ...
EJC
2016
8 years 4 months ago
2016
For r ≥ 2, an r-uniform hypergraph is called a friendship r-hypergraph if every set R of r vertices has a unique ‘friend’ – that is, there exists a unique vertex x /∈ R ...