Non-Traditional Squares of Predication and Quantification

Three logical squares of predication or quantification, which one can even extend to logical hexagons, will be presented and analyzed. All three squares are based on ideas of the non-traditional theory of predication developed by Sinowjew and Wessel. The authors also designed a non-traditional theory of quantification. It will be shown that this theory is superfluous, since it is based on an obscure difference between two kinds of quantification and one pays a high price for differentiating in this way: losing the definability between the existence- and all-quantifier. Therefore, a combination of non-traditional predication and classical quantification is preferred here.      

Sampling measures for Bergman spaces on the unit disk

We provide a characterization of the sampling measures for the Bergman spaces. These are the positive measures on the unit disk for which there exists a constant such that These are the continuous analogues of the sets of sampling characterized by K. Seip [13,14] and A. Schuster [12]. Our characterization is in terms of weak* limits of the Moebius transformations of the measure , and mimics the notion for sequences that sampling means being uniformly far from zero sets. Received: 26 October 1998 / in revised form: 25 Juni 1999     

Tolerance space theory and some applications

The paper deals with the notion of tolerance space (introduced by E. C. Zeeman, but discerned earlier by H. Poincaré), which formalizes the idea of resemblance. The category of tolerance spaces is described, their homology and homotopy theories developed. Applications include almost-fixed point theorems, almost-solution existence theorems for difference schemes and the three-channel principle (a general theorem on multichannel data transmission).     

D-strong and almostD-strong near-rings

In this paper,D-strong and almostD-strong near-rings have been defined. It has been proved that ifR is aD-strongS-near ring, then prime ideals, strictly prime ideals and completely prime ideals coincide. Also ifR is aD-strong near-ring with identity, then every maximal right ideal becomes a maximal ideal and moreover every 2-primitive near-ring becomes a near-field. Several properties, chain conditions and structure theorems have also been discussed.Most of the parts of this paper are included in author's doctoral dissertation at Sukhadia University Udaipur (1983). The author expresses his gratitude to Dr.S. C. Choudhary for his kind guidance.     

Minimizing bumps in linear extensions of ordered sets

A linear extension x ₁ x ₂ x ₃ ... of a partially ordered set (X, <) has a bump whenever x _i <x _i +1. We examine the problem of determining linear extensions with as few bumps as possible. Heuristic algorithms for approximate bump minimization are considered.     

Nonlinear vibrations of offshore structures under random wave excitation

An account is given of some mathematical methods which have been used to analyse the response of offshore structures to random wave excitation. The analysis of nonlinear phenomena and the assessment of related nongaussian probability distributions are emphasized. The following problems are analysed in some depth: probability distributions for Morison-type wave loading; response near resonance of nonlinearly damped systems to random excitation; parametric resonance and instability of nonlinearly damped systems with randomly fluctuating restoring force coefficient. Solutions to each of these problem areas are illustrated by practical examples.     

New Examples of Non-complete Pick Kernels

We construct continuous families of non-complete Pick kernels on countable sets and show that they are preserved by an operation introduced by S. Shimorin. In the infinite case the multiplier algebra is l^∞ and there exist non-constant multipliers whose operator norms equal their supremum norms.     

Direct and Inverse Spectral Theory of One-dimensional Schrödinger Operators with Measures

We present a direct and rather elementary method for defining and analyzing one-dimensional Schrödinger operators H = −d²/dx² + μ with measures as potentials. The basic idea is to let the (suitably interpreted) equation −f′′ + μ f = zf take center stage.We show that the basic results from direct and inverse spectral theory then carry over to Schrödinger operators with measures.