We show that the three body Calogero model with inverse square potentials can be interpreted as a maximally superintegrable and multiseparable system in Euclidean three-space. As such it is a special case of a family of systems involving one arbitrary function of one

Motivated by the well-known conjecture by Lovász [6] on the connectivity after the path removal, we study the following problem: There exists a function f = f(k, l) such that the following holds. For every f(k, l)connected graph G and two distinct vertices s and t in G, there are k internally disjoint paths P1, . . . , Pk with endpoints s and t such that G− ⋃k i=1 V (Pi) is l-connected. When k ...

We formulate a reconstruction problem for functions of several arguments: Is a function of several arguments uniquely determined, up to equivalence, by its identification minors? We establish some positive and negative results on this reconstruction problem. In particular, we show that totally symmetric functions (of sufficiently large arity) are reconstructible.

‎In this paper‎, ‎we investigate the number of 1-factors of a‎ ‎generalized Petersen graph $P(N,k)$ and get a lower bound for the‎ ‎number of 1-factors of $P(N,k)$ as $k$ is odd‎, ‎which shows that the‎ ‎number of 1-factors of $P(N,k)$ is exponential in this case and‎ ‎confirms a conjecture due to Lovász and Plummer (Ann‎. ‎New York Acad‎. ‎Sci‎. ‎576(2006)‎, ‎no‎. ‎1‎, ‎389-398).

For a finite group $G$‎, ‎let $Cent(G)$ denote the set of centralizers of single elements of $G$‎. ‎In this note we prove that if $|G|leq frac{3}{2}|Cent(G)|$ and $G$ is 2-nilpotent‎, ‎then $Gcong S_3‎, ‎D_{10}$ or $S_3times S_3$‎. ‎This result gives a partial and positive answer to a conjecture raised by A‎. ‎R‎. ‎Ashrafi [On finite groups with a given number of centralizers‎, ‎Algebra‎ ‎Collo...