For positive semidefinite matrices A and B, Ando and Zhan proved the inequalities |||f(A) + f(B)||| ≥ |||f(A + B)||| and |||g(A) + g(B)||| ≤ |||g(A + B)|||, for any unitarily invariant norm, and for any non-negative operator monotone f on [0,∞) with inverse function g. These inequalities have very recently been generalised to non-negative concave functions f and non-negative convex functions g,...

Given a graph property $\Phi$, the problem $\#\ensuremath{{\sc IndSub}}(\Phi)$ asks, on input of $G$ and positive integer $k$, to compute number $\#{\ensuremath{{IndSub}({\Phi,k} \to {G})}}$ induced subgraphs size $k$ in that satisfy $\Phi$. The search for explicit criteria $\Phi$ ensuring is hard was initiated by Jerrum Meeks [J. Comput. System Sci., 81 (2015), pp. 702--716] part major line re...

The subject is the overview of the use of quasi-entropy in finite dimensional spaces. Operator monotone functions and relative modular operators are used. The origin is the relative entropy, and the f -divergence, monotone metrics, covariance and the χ2-divergence are the most important particular cases. The extension of monotone metrics to those with two parameters is a new concept. Monotone m...

In this paper, by reducing of coincidence and coupled fixed point results in ordered metric spaces to the respective results for mappings with one variable, some recent results established by T. G. Bhaskar and V. Lakshmikantham [T. G. Bhaskar, V. Lakshmikantham, Fixed point theorems in partially ordered metric spaces and applications, Nonlinear Analysis 65 (2006) 1379-1393], V. Lakshmikantham a...

*Correspondence: [email protected] Department of Mathematics, Hashemite University, Zarqa, Jordan Abstract In this paper, we prove some quadruple coincidence and quadruple common fixed point theorems for F : X4 → X and g : X → X satisfying (φ –ψ ) contractions in partially ordered G-metric spaces. We illustrate our results based on an example of the main theorems. Also, we deduce quadruple coi...

Given a property P of graphs, write Pn for the set of graphs with vertex set [n] having property P. We call |Pn| the speed of P. Recent research has shown that the speed of a monotone or hereditary property P can be a constant, polynomial, or exponential function of n, and the structure of the graphs in P can then be well described. Similarly, |Pn| can be of the form n(1−1/k+o(1))n or 2(1−1/k+o...

A graph G = (V,E) is said to be saturated with respect to a monotone increasing graph property P, if G / ∈ P but G ∪ {e} ∈ P for every e ∈ ( V 2 ) \ E. The saturation game (n,P) is played as follows. Two players, called Mini and Max, progressively build a graph G ⊆ Kn, which does not satisfy P. Starting with the empty graph on n vertices, the two players take turns adding edges e ∈ ( V (Kn) 2 )...