No Arabic abstract
We consider integrals $tau_{rho}=int_0^1rhoxi^2,dx$, where $xi$ is Wiener process and $rho$ is generalized function from some class of multipliers. In the case when multiplier $rho$ belongs to the trace-class, it is shown that $tau_{rho}$ has $chi^2$-distribution (or analogous). An example of multiplier $rho$ not belonging to the trace-class is constructed.
The two parameters quantum algebra $SU_{p,k}(2)$ can be obtained from a single parameter algebra $SU_q(2)$. This fact gives some relations between $SU_{p,k}(2)$ quantities and the corresponding ones of the $SU_q(2)$ algebra. In this paper are mentioned the relations concerning: Casimir operators, eigenvectors, matrix elements, Clebsch Gordan coefficients and irreducible tensors.
We look at periodic Jacobi matrices on trees. We provide upper and lower bounds on the gap of such operators analogous to the well known gap in the spectrum of the Laplacian on the upper half-plane with hyperbolic metric. We make some conjectures about antibound states and make an interesting observation for what [3] calls the rg-model.
Let $G$ be a connected undirected graph with $n$, $nge 3$, vertices and $m$ edges. Denote by $rho_1 ge rho_2 ge cdots > rho_n =0$ the normalized Laplacian eigenvalues of $G$. Upper and lower bounds of $rho_i$, $i=1,2,ldots , n-1$, are determined in terms of $n$ and general Randi c index, $R_{-1}$.
We exhibit a particular free subarrangement of a certain restriction of the Weyl arrangement of type $E_7$ and use it to give an affirmative answer to a recent conjecture by T.~Abe on the nature of additionally free and stair-free arrangements.
The twin group $T_n$ is a right angled Coxeter group generated by $n- 1$ involutions and having only far commutativity relations. These groups can be thought of as planar analogues of Artin braid groups. In this note, we study some properties of twin groups whose analogues are well-known for Artin braid groups. We give an algorithm for two twins to be equivalent under individual Markov moves. Further, we show that twin groups $T_n$ have $R_infty$-property and are not co-Hopfian for $n ge 3$.