This article is an overview of the current state of typological research on negation. Structures expressing standard negation – the negation of declarative verbal main clauses – can be classified on the basis of the status of the negative marker, or on the basis of the structure of the negative clause as a whole. Structural similarities and differences (symmetry and asymmetry) between negatives...

We consider the nonlinear beam equation utt + a(x)ut − f(ux)x + uxxxx = 0 in a bounded interval (0, 1) ⊂ R. The equation has an indefinite damping term, i.e., with a damping function a = a(x) possibly changing sign. For this non-dissipative situation we prove the exponential stability of the corresponding linearized system provided ā = ∫ 1 0 a(x)dx > 0 and ‖ a− ā ‖L2≤ τ , for τ small enough. We...

It is shown that, for any given polynomially normal matrix with respect to an indefinite inner product, a nonnegative (with respect to the indefinite inner product) invariant subspace always admits an extension to an invariant maximal nonnegative subspace. Such an extension property is known to hold true for general normal matrices if the nonnegative invariant subspace is actually neutral. An e...

The paper summarizes and generalizes a recently proposed mathematical framework that unifies the standard formalisms of special relativity and quantum mechanics. The framework is based on Hilbert spaces H of functions of four space-time variables x, t, furnished with an additional indefinite inner product invariant under Poincaré transformations, and isomorphisms of these spaces that preserve t...

This paper discusses a dual-stage detection scheme composed of coarse detection stage and refined detection stage for the continuous detection operation of Ultra-Wideband (UWB) detect and avoid (DAA). The threshold factor for the probability of indefinite detection is first proposed and defined to combine the two stages. The proposed scheme focuses on the integration of two different detection ...