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Let $\kappa$ be an uncountable cardinal with $\kappa=\kappa^{{\kappa^+$'' implies the statement "every closed subset of ${}^\kappa\kappa$ is a continuous image of ${}^\kappa(\kappa^+)$'' or its negation., Comment: 30 pages

In this paper, we prove the Hyers–Ulam stability of some set-valued functional equations.

The concept of table algebra in the title is a real nonsingular generalized table algebra in the sense of [Z. Arad, E. Fisman, M. Muzychuk, Generalized table algebras, Israel J. Math. 114 (1999) 29–60]. In this paper we first give some definitions and facts about table algebras. It is well known that every association scheme gives a Hecke-algebra which is a table algebra too. This leads to the natural question which properties of association schemes stay valid for table algebras. For instance, we prove the Second Isomorphism Theorem and the Jordan–Holder's theorem for standard table algebras.

The sets of compact and of closed subsets of a metric space endowed with the Hausdorff metric are studied. Both give rise to a functor on the category of 1-bounded metric spaces and nonexpansive functions. It is shown that the former functor has a terminal coalgebra and that the latter does not.

In 1934, Whitney raised the question of how to recognize whether a function f defined on a closed subset X of Euclidean space is the restriction of a function that is continuously differentiable to order p. A necessary and sufficient criterion was given in the case n=1 by Whitney, using limits of finite differences, and in the case p=1 by Glaeser (1958), using limits of secants. We introduce a necessary geometric criterion, for general n and p, involving limits of finite differences, that we conjecture is sufficient at least if X has a "tame topology". We prove that, if X is a compact subanalytic set, then there exists q=q(p) such that the criterion of order q implies that f is p times continuously differentiable. The result gives a new approach to higher-order tangent bundles (or bundles of differentiable operators) on singular spaces., AMS-TEX, 28 pages

Let F be a closed subset of the unit circle T and let f∈C(F). We investigate the problem of uniform approximation of f on F by polynomials Pn which are uniformly bounded on the unit disk Δ. In a particular case when F is a closed arc of T, the problem was solved by L. Zalcman in 1982, who has also pointed out the possibility of considering more general approximation sets instead of an arc. The present paper gives a necessary and sufficient solution of the above problem. In fact we show that the (simple) description of f given by Zalcman for the case of an arc also holds in the general case.

Let A be a closed subset of the plane. For a point b in the plane whose distance to A is d(b,A) let S(b,A) = {z : |z-b| d (b,A)}. Let E(A) be the set of points e for which S(b,A) ∩ A has at least two points. Let f(A) be the set of open intervals (a,b) for which there is an e ℇ E(A) and a component of S(e,A)-A with endpoints a and b. The sets E(A) and f(A) are the central tools in this paper.