we define a new type of spectrum, called δ-approximate spectrum, of an element a in a complex unital banach algebra a and show that the δ-approximate spectrum σ_δ (a) of a is compact. the relation between the δ-approximate spectrum and the usual spectrum is investigated. also an analogue of the classical gleason-kahane-zelazko theorem is established: for each ε>0, there is δ>0 such that if ϕ is...

Spectrum Inference in contrast to Sensing is an active technique for dynamically inferring radio spectrum state Cognitive Radio Networks. Efficient inference demands real world multi-dimensional spectral data with distinct features. bands exhibit varying noise floors; effective band wise thresholding guarantees accurate occupancy data. In this work, we have done extensive measurement frequency ...

We present a “separation” algorithm for achieving color constancy and theorems concerning its accuracy. The algorithm requires extra information from the optical system, over and above the usual three values mapping human cone responses. However, with this additional information-specifically, a sampling across the visible range of the reflected, color-signal spectrum impinging on the optical se...

form the base of a topology on the Stone spectrum Q(R) such that Q(R) becomes a zero-dimensional, completely regular Hausdorff space. The sets QP (R) are closed-open. If the von Neumann algebra R is abelian, then the Stone spectrum Q(R) is homeomorphic to the Gelfand spectrum Ω(R) of R. For an arbitrary non-abelian unital von Neumann algebra R, the Stone spectrum can hence be regarded as a non-...

We investigate whether quasinormal modes (QNMs) can be used in the search for signatures of extra dimensions. To address a gap Beyond Standard Model (BSM) literature, we focus here on higher dimensions characterised by negative Ricci curvature. As first step, consider product space comprised four-dimensional Schwarzschild black hole space-time and three-dimensional nilmanifold (twisted torus); ...