On strong pseudomonotonicity and (semi)strict quasimonotonicity

An example in Ref. 1 is corrected to show that indeed a strongly pseudoconvex function, which is only once but not twice differentiable, does not necessarily have a strongly pseudoconvex gradient.     

Supplement to a critique of Piron's system of questions and propositions

A previous critique of the relevance of Piron's questions-propositions system as a generator of quantum mechanics by interpretation is reinforced and brought to a close by further investigation.     

Properties of mixtures on non-orthogonal states

We study the density operators expressed as mixtures of non-orthogonal pure states in quantum mechanics. The general mathematical law of formation of such mixtures is found. Applications are given concerning the entropy properties of density operators etc.     

Aris Daniilidis

Discussion

Aris Daniilidis Universitat Autònoma de Barcelona, Spain     

Transformation of Quasiconvex Functions to Eliminate Local Minima

Quasiconvex functions present some difficulties in global optimization, because their graph contains “flat parts”; thus, a local minimum is not necessarily the global minimum. In this paper, we show that any lower semicontinuous quasiconvex function may be written as a composition of two functions, one of which is nondecreasing, and the other is quasiconvex with the property that every local minimum is global minimum. Thus, finding the global minimum of any lower semicontinuous quasiconvex function is equivalent to finding the minimum of a quasiconvex function, which has no local minima other than its global minimum. The construction of the decomposition is based on the notion of “adjusted sublevel set.” In particular, we study the structure of the class of sublevel sets, and the continuity properties of the sublevel set operator and its corresponding normal operator.     

Some Conditions for Maximal Monotonicity of Bifunctions

We present necessary and sufficient conditions for a monotone bifunction to be maximally monotone, based on a recent characterization of maximally monotone operators. These conditions state the existence of solutions to equilibrium problems obtained by perturbing the defining bifunction in a suitable way.     

Coercivity conditions and variational inequalities

Received November 17, 1997 / Revised version received August 6, 1998?Published online March 16, 1999     

Über die Existenz gemeinsamer Elemente bester Approximation bezüglich zweier Normen II

The present paper deals with the possibility of existence of best approximation elements, simultaneously with respect to two norms ·_i,i=1,2, for all the elements of a class of subspaces. In case this class in any of the following: (a) All n-dimensional subspaces, (b) All ·₁-or ·||₂-closed, n-codimensional subspaces, (c) All ·₁-or ·₂-closed subspaces with infinite dimension and codimension, we prove that the two norms differ at most by a constant factor.