We show that if G is a stable group of finite weight with no infinite, infinite-index, chains of definable subgroups, then G is superstable of finite U rank. Combined with recent work of Palaćın and Sklinos, we conclude that (Z,+, 0) has no proper stable expansions of finite weight. A corollary of this result is that if P ⊆ Zn is definable in a finite dp-rank expansion of (Z,+, 0), and (Z,+, 0,...

In this paper, we study VC-density over indiscernible sequences (denoted VCind-density). We answer an open question in [1], showing that VCind-density is always integer valued. We also show that VCind-density and dp-rank coincide in the natural way.

Let k be a field of characteristic q, C a smooth connected curve defined over k with function field K := k(C). Let A/K be a non constant abelian variety defined over K of dimension d. We assume that q = 0 or > 2d + 1. Let p 6= q be a prime number and C → C a finite geometrically Galois and étale cover defined over k with function field K ′ := k(C). Let (τ , B) be the K /k-trace of A/K. We give ...

This communication deals with the problem of state estimation for a class of non linear singular systems. Sufficient conditions for the existence of such observers are provided and the design of an observer is examined. Assuming that the measurement matrix is full row rank involves many calculation simplifications ; therefore special emphasis in the computational aspect of the observer matrices...

In this paper we investigate some matrix structures on C that have a good behaviour under Schur complementation. The first type of structure is closely related to low displacement rank matrices. Next, we show that for a matrix having a low rank submatrix, also the Schur complement must have a low rank submatrix, which we can explicitly determine. This property holds even if the low rank submatr...

We propose a method for rank k approximation to a given input matrix X P R which runs in time