in the present paper, we introduce the sequence space [{l_p}(e,delta) = left{ x = (x_n)_{n = 1}^infty : sum_{n = 1}^infty left|  sum_{j in {e_n}} x_j - sum_{j in e_{n + 1}} x_jright| ^p < infty right},] where $e=(e_n)$ is a partition of finite subsets of the positive integers and $pge 1$. we investigate its topological properties and inclusion relations. moreover, we consider the problem of fin...

Abstract The spectrum of a real and symmetric $$N\times N$$ N × matrix determines the up to unitary equivalence. More spectral data is needed together with some sign indicators remove ambiguities. In first part this work, we specify information required for unique recon...