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Ilya Bogdanov

Publications and source records attributed to Ilya Bogdanov.

5 recordsLinked to original sources

The continualization approach to the on-line hypergraph coloring

The paper deals with an algorithmic problem concerning combinatorial game theory. Here we introduce and analyze a continuous generalization of Chip Game from the work of Duraj, Gutowski and Kozik. The general Chip game was introduced by Aslam and Dhagat to model on-line type problems on hypergraph coloring.

math.CO

Covering three-tori with cubes

Let $μ(\varepsilon)$ be the minimum number of cubes of side $\varepsilon$ needed to cover the unit three-torus $[\mathbb{R}/\mathbb{Z}]^3$. We prove new lower and upper bounds for $μ(\varepsilon)$ and find the exact value for all $\varepsilon\geq\frac{7}{15}$ and all $\varepsilon\in\left[\frac{1}{r+1/(r^2+r+1)},\frac{1}{r-1/(r^2-1)}\right)$ for any integer $r\geq 2$.

math.CO

Feynman checkers: the probability of direction reversal

We study the most elementary model of electron motion introduced by R.Feynman in 1965. It is a game, in which a checker moves on a checkerboard by simple rules, and we count the turnings. The model is also known as one-dimensional quantum walk. In his publication, R.Feynman introduces a discrete version of path integral and poses the problem of computing the limit of the model when the lattice step and the average velocity tend to zero and time tends to infinity. We get a nontrivial advance in the problem on the mathematical level of rigor in a simple particular case; even this case requires methods not known before. We also prove a conjecture by I.Gaidai-Turlov, T.Kovalev, and A.Lvov on the limit probability of direction reversal in the model generalizing a recent result by A.Ustinov.

math.PR

Analysis of Relaxation Time in Random Walk with Jumps

We study the relaxation time in the random walk with jumps. The random walk with jumps combines random walk based sampling with uniform node sampling and improves the performance of network analysis and learning tasks. We derive various conditions under which the relaxation time decreases with the introduction of jumps.

math.PR

Solvability of cubic and quartic equations using one radical

Theorem. An irreducible cubic polynomial with rational coefficients has a root in a one step radical extension of Q if and only if the discriminate is a square of a rational number. Theorem. An irreducible polynomial x^4+px^2+qx+s with rational coefficients q\ne0, p and s has a root in a one step radical extension of Q if and only if the cubic resolution has rational root t such that t>p/2 and A:=16(t^2-s)^2-(t^2-s)(2t+p)^2 is a square of a rational number.

math.HO