We adjoin a point at infinity to a field with a ring topology and extend the topology by taking complements of bounded sets as neighbourhoods of infinity. We note some elementary relations between the topology on the field and the topology on the field with infinity adjoined.

We discuss permutation properties of a specific kind of binomials over finite fields. As a result, we complete Cavior's classification of binomial octic permutation polynomials over Fq with q odd.

A C*-algebra A is finite-dimensional if and only if the cone is closed in M2 ⊗ A.

We characterise continuous closed (perfect, open) functions in terms of nets. This enables us to improve some significant results, with much simpler proofs.

Sufficient conditions are obtained for the stability of linear neutral delay-differential systems by using a delay-differential inequality.

Let X be an affine real algebraic variety. In this paper, assuming that dim X ≤ 7 and that X satisfies some other reasonable conditions, we give a characterisation of those continuous complex vector bundles on X which are topologically isomorphic to algebraic complex vector bundles on X.

We consider the Abelian functional equation

where φ is a given entire function and g is to be found. The inverse function f = g−1 (if one exists) must satisfy

We show that for a wide class of entire functions, which includes φ(z) = ez − 1, the latter equation has a non-constant entire solution.

We improve S. Yamashita's hyperbolic version of the well-known Hardy-Littlewood theorem. Let f be holomorphic and bounded by one in the unit disc D. If (f#)p has a harmonic mojorant in D for some p, p > 0, then so does σ(f)q for all q, 0 < q < ∞. Here

An algorithm which has been developed to solve the problem of determining an optimal path of the hand of a robot is applied to various classical problems in the calculus of variations.

The generic closure of the set of primes contracted from the complete ring of quotients of a reduced commutative ring is shown to be just the set of those primes not containing a finitely generated dense ideal. It is also the smallest generically closed, quasi-compact set containing the minimal primes.

Point symmetries and reflections are two important transformations on a Riemannian manifold. In this article we study the interactions between point symmetries and reflections in a compact symmetric space when the reflections are global isometries.

The multivariate stochastic ordering induced by the convex nondecreasing functions compares a combination of size and variability of random vectors. Closely following methods developed by Strassen, we show that two probability measures are ordered in this way if and only if they are the marginals of some submartingale. The implications of this in majorisation theory are discussed.

A simple characterisation is given of compact sets of the space K(X), of nonempty compact subsets of a complete metric space X, with the Hausdorff metric dH. It is used to give a new proof of the Blaschke selection theorem for compact starshaped sets.

In this note two theorems of Ma and Fan concerning sets with convex sections are generalised.

Let Ω denote the closed interval [0, 1] and let bA denote the set of all bounded, approximately continuous functions on Ω. Let Q denote the Banach space (sup norm) of quasi-continuous functions on Ω. Let M denote the closed convex cone in Q comprised of non-decreasing functions. Let hp, 1 < p < ∞, denote the best Lp-simultaneaous approximation to the bounded measurable functions f and g by elements of M. It is shown that if f and g are elements of Q, then hp converges unifornily to a best L1-simultaneous approximation of f and g. We also show that if f and g are in bA, then hp is continuous.

The p-norm of the Hilbert transform is the same as the p-norm of its truncation to any Lebesgue measurable set with strictly positive measure. This fact follows from two symmetry properties, the joint presence of which is essentially unique to the Hilbert transform. Our result applies, in particular, to the finite Hilbert transform taken over (−1, 1), and to the one-sided Hilbert transform taken over (0, ∞). A related weaker property holds for integral operators with Hardy kernels.

The “type II conjecture”, proposed by J. Rhodes, gives an algorithm to compute the kernel of a given finite semigroup. We show that this conjecture is a consequence of another conjecture, of a topological nature. This new conjecture gives a simple and effective characterisation of the recognisable subsets of a free monoid that are closed in the finite group topology for the free monoid.

We show that while farthest points always exist in w* -compact sets in duals to Radon-Nikodym spaces, this is generally not the case in dual Radon-Nikodym spaces. We also show how to characterise weak compactness in terms of farthest points.

Each ring contains a unique smallest ideal which when factored out yields a ring with zero middle annihilator. Various results concerning this ideal are obtained including theorems about how it behaves in connection with normalising extensions and smash products.

Let f be a function meromorphic in D = {|z| < 1} and let X be the chordal distance on the Riemann sphere. Then f satisfies the Lipschitz condition

in D if and only if |f′(z)|/(1 + |f(z)|2) = O((1 – |z|)α−1) and |z| → 1.