Expansions of generalized functions have been investigated by many authors. Korevaar [11], Widlund [20], Giertz [8], Walter [19] developed procedures for expanding generalized functions of Korevaar [12], Temple [17], and Lighthill [13], Expansions of certain Schwartz distributions [15] into series of orthonormal functions were given by Zemanian [23] (see also Zemanian [24]) and thereby he extended a number of integral transforms to distributions. The method involved in his work is very much related to the Hilbert space technique and is of somewhat different character from those used in most of the works on integral transforms such as [24, chapters 1-8]. Other works that discuss orthogonal series expansions involving generalized functions are by Bouix [1, chapter 7], Braga and Schönberg [2], Gelfand and Shilov [7, vol. 3, chapter 4] and Warmbrod [21].

S. Lie a étudié méthodiquement, pour la première fois, des propriétés des équations différentielles invariantes par les groupes continus de transformations locales (pseudo-groupes continus). Après avoir étudié la structure des pseudo-groupes, Lie a esquissé la méthode générale d’intégration des équations différentielles, [9]. Un de ses idées fondamentales est celle de réduire les équations différentielles aux autres équations faciles à étudier : par exemple, les systèmes de Pfaff complètement intégrables.

In his study on the structure of the complex Lie algebra of holomorphic vector fields on a compact Kähler manifold, Lichnerowicz ([3] Theorem 2, see also [1] and [4]) shows that if the first Chern class of the manifold is positive semi-definite, then to each harmonic (O.l)-form (i.e. anti-holomorphic 1-form) η, there exists a holomorphic vector field X such that the (O.1)-form i(X)k is d″-cohomologous to η, where k is the Kähler form. The purpose of this note is to indicate that this result is a consequence of an existence theorem for solutions of a certain self-adjoint elliptic partial differential equation.

Let k be a field and let A = be a normal graded subring of the full ring of polynomials R = k[X1, · · ·, Xn] (where R always is graded via total degree and A0 = k). R. Fossum and the author [F-G] observed that the completion  at the irrelevant maximal ideal of A is isomorphic to the subring of the formal power series ring R̂ = k[[X1, · ·., Xn]] and, moreover, that  is a ring of invariants of an algebraic group whenever A is.

Let ⌈ be a subgroup of the modular group PSL(2,Z) then ⌈ acts on the upper half plane H = {zЄC : Im z > 0} and we can form the Riemann surface M = H/⌈, see [3]. The complex line bundles on a Riemann surface M form a group H1(M, *), see [4], and whenever we raise a line bundle to a power it will be in this group. Let κ denote the canonical bundle on M then a modular form of weight ν is a section of the bundle . A modular n-jet is then a section of Jn the n-th jet bundle, see [7]. We can reformulate these ideas in the following terms. A modular form can be viewed as a function Φ: H → C and a modular n-jet as a vector valued function Φ: H → Cn+1 both of which satisfy a transformation law under the elements of Γ.

Hironaka, in his paper [H1] on desingularization of algebraic varieties over a field of characteristic 0, to deal with singular points develops the algebraic apparatus of the associated graded ring, introducing standard bases of ideals, numerical characters ν* and τ* etc. Such a point of view involves a deep investigation of the ideal b* generated by the initial forms of the elements of an ideal A of a local ring, with respect to a certain ideal a.

A. Friedman, [5] has constructed the fundamental solutions for a class of degenerate parabolic equations of the second order by making use of a probabilistic method and obtained the estimates for the fundamental solutions, especially near the degenerating manifolds (obstacles) of given operators, where a probabilistic method plays an important role.

In the traditional study of Łukasiewicz propositional logic, the finite-valued or infinite-valued linearly ordered model exists at the start, and then the axiomatization of the set of all formulas valid in its model are studied. On the other hand, we are in a point of view such that the set of provable formulas is important and models are no more than means to characterize the set.