B. San Martin

TL;DR: A lower bound for the energy of a symmetric matrix partitioned into blocks is introduced and some computational experiments are presented in order to show that the obtained lower bound is incomparable with the well known lower bound 2m.

TL;DR: In this article, a new spectral graph invariant sprR, called Randić spread, is defined and investigated, which is equal to the maximal difference between two eigenvalues of the randić matrix, disregarding the spectral radius.

TL;DR: In this paper, the authors characterize the N-expansive systems as those homeomorphisms for which every Borel probability measure is N-Expansive and derive a lower bound of the topological entropy of the N expansive flows as the exponential growth rate of the number of periodic orbits.

TL;DR: In this article, the authors consider two kinds of complex singular cycles arising for vector fields defined on three-dimensional manifolds and prove that any one parameter family of vector fields passing through these cycles has the following property: Hyperbolicity is a prevalent phenomena.