The heat equation is to be solved in a severaldimensional region D with on the boundary B of D. The elementary solution (Green’s function) is interpreted as the transition density of an associated Brownian motion. The latter is built up pathwise from the free Brownian motion by simple geometric and probabilistic transformations.

It is our object in this paper to show that the recent results of K. Ito and M. Nisio [4] on the oscillation function of Gaussian processes on [0,1] are valid for Gaussian processes with a general multiparameter “time” set T. Except in extending Theorem 4 of [4] where we assume T to be the d-dimensional cube, in all other cases we allow T to be a separable metric space. Despite the generality of the time set, the proofs are achieved essentially using the method of the above mentioned authors. However, in Theorem 1 below we find the use of Lemma 6 of [5] more convenient than the approach via orthogonal expansions and Kolmogorov’s zero-one law as is done in [4].

Let k be an algebraically closed field, and X a nonsingular irreducible protective algebraic variety over k. These assumptions will remain fixed throughout this paper. We will consider a family of vector bundles on X of fixed rank r and fixed Chern classes (modulo numerical equivalence). Under what condition is this family a bounded family? When X is a curve, Atiyah [1] showed that it is so if all elements of this family are indecomposable. But when I is a surface, he showed also that this condition is not sufficient. We give the definition of an H-stable vector bundle on a variety X. This definition is a generalization of Mumford’s definition on a curve. Under the condition that all elements of a family are H-stable of rank two on a surface X, we prove that the family is bounded. And we study H-stable bundles, when X is an abelian surface, the protective plane or a geometrically ruled surface.

We consider continuous functions f which map the open unit disk D into the Riemann sphere W. For a point ζ on the unit circle C, we say that χ is a chord at ζ if χ is a chord of C having one endpoint at ζ and that Δ is a Stolz angle at ζ if Δ is a Stolz angle with vertex ζ. Suppose S denotes either a chord at ζ, a Stolz angle at ζ, or D.

Soit X un espace localement compact et dénombrable à l’infini, et supposons qu’il existe une mesure de Radon positive ξ partout dense dans X. Dans toute la suite X et ξ seront fixés.

Cette mémoire sera consacrée à l’etude sur l’existence et la nonexistence des alg’bres de Dirichlet sur un ouvert de l’espace euclidien Rn à n(≧1) dimensions. La notion des algèbres de Dirichlet a été introduite par A. Beurling et J. Deny (cf. [1]).

According to [4] a meromorphic function h(z) = f(g)(z) is said to have f(z) and g(z) as left and right factors respectively, provided that f(z) is non-linear and meromorphic and g(z) is non-linear and entire (g may be meromorphic when f(z) is rational). h(z) is said to be E-prime (E-pseudo prime) if every factorization of the above form into entire factors implies that one of the functions f, or g is linear (polynomial). h(z) is said to be prime (pseudo-prime) if every factorization of the above form, where the factors may be meromorphic, implies that one of f or g is linear (a polynomial or f is rational).

Recent results of Hoffman and Singer [7], Weiss [10] and Wilken [11] indicate that the study of separation properties play a central rôle in the theory of function algebras. Our purpose in this paper is to investigate a natural separation property of function algebras.

The stability of the systems given by ordinary differential equations or functional-differential equations has been studied by many mathematicians. The most powerful tool in this field seems to be the Liapunov’s second method (see, for example [6]).

Dans ce mémoire, on étend quelques résultats obtenus dans [10] au système et comme application, on considère sur la somme de fonctions normales.

En Géométrie Algébrique on a un critère pour qu’une surface moins une courbe soit affiine (Hartshorne (5)). Dans (5), on demande s’il existe un analogue analytique. Le but de cet article est de donner une condition numérique necessaire pour les surfaces complexes compactes (Théorème 1) et une condition suffisante pour les surfaces réglées (Théorème 2).

Let M be a connected surface immersed in a Euclidean m-space Em. Let h be the second fundamental form of this immersion it is a certain symmetric bilinear mapping for X ∈ M, where Tx is the tangent space and the normal space of M at x. Let H be the mean curvature vector of M in Em. If there exists a real λ such that for all tangent vectors X, Y in Tx, then ilf is said to be pseudo-umbilical at x.

In this paper, we shall supply proofs to the results announced in [2], pp. 74-75: we shall prove the Siegel formula for the Pfaffian of degree n over an algebraic number field and also determine the zeta function of the Pfaffian. In the appendix, we shall briefly discuss the non-split case where the Pfaffian is replaced by the norm form of the simple Jordan algebra of quaternionic hermitian matrices of degree n.

The interpretations of simplicial cohomology groups for associative commutative algebras and for Lie algebras were given by Beck [2], Iwai [9] and Shimada and others [15,16]. On the other hand, Jonah [10] gave a formulation and an interpretation of the second and third cohomology groups of an associative coalgebra after the Hochschild’s treatment [5 ∽ 8].

Let ξ(t), t ∈ T, be a Gaussian process on a set T, and H = H(ξ) be the closed linear manifold generated by all values ξ(t), t ∈ T, with the inner product