The vertices of the commuting graph of a semigroup S are the noncentral elements of this semigroup, and its edges join all pairs of elements g, h that satisfy the relation gh = hg. The paper presents a proof of the fact that the diameter of the commuting graph of the semigroup of real matrices of order n ≥ 3 is equal to 4. A survey of results in that subject matter is presented, and several open problems are formulated.
In this paper, we consider quantum multidimensional problems solvable by using the second quantization method. A multidimensional generalization of the Bogolyubov factorization formula, which is an important particular case of the Campbell–Baker–Hausdorff formula, is established. The inner product of multidimensional squeezed states is calculated explicitly; this relationship justifies a general construction of orthonormal systems generated by linear combinations of squeezed states. A correctly defined path integral representation is derived for solutions of the Cauchy problem for the Schrödinger equation describing the dynamics of a charged particle in the superposition of orthogonal constant (E,H)-fields and a periodic electric field. We show that the evolution of squeezed states runs over compact one-dimensional matrix-valued orbits of squeezed components of the solution, and the evolution of coherent shifts is a random Markov jump process which depends on the periodic component of the potential.
We examine homogeneous cosmological models with arbitrary (uniform) motion of matter. We have shown the presence of an oscillatory mode of the BLK type when moving toward a cosmological singularity in models of II–IV and VI–IX Bianchi types. We have formulated constraints on the velocities under which the oscillatory mode degenerates to Kästner asymptotics.
This communication is devoted to establishing the very first steps in study of the speed at which the error decreases while dealing with the based on the Chernoff theorem approximations to one-parameter semigroups that provide solutions to evolution equations.
The study of the spectral properties of operator polynomials is reduced to the study of the spectral properties of the operator specified by the operator matrix. The results obtained are applied to higher-order difference operators. Conditions for their invertibility and for them to be Fredholm, as well as the asymptotic representation for bounded solutions of homogeneous difference equations are obtained.
A problem of complexity of Boolean functions realization over infinite complete bases of special type is studied. These bases contain all monotone functions with zero weight and finite number of non-monotone functions with unit weight. Exhaustive description of Boolean realization over basis that consists of all monotone functions and one non-monotone function negation has been obtained by Markov. The minimal sufficient number of negations for arbitrary Boolean function f realization (i.e. inversion complexity of the function f) equals ⌈log2(d(f)+1)⌉, where d(f) is the maximal number of function value changes from 1 to 0 over all increasing chains of tuples of variables values. In this paper the result above is generalized to the arbitrary basis of this type. It is shown that the minimal sucient for arbitrary Boolean function f realization number of non-monotone functions equals ⌈log2(d(f)/D(B) + 1)⌉. Here D(B) is the maximum d(ω) over all non-monotone functions ω from the basis B.