In this paper a new generalization of the Meijer transform is given. It also generalizes the Mainra transform and the transform due to Varma. An inversion theorem is established and the result obtained has been illustrated by several examples.

We consider a stochastically continuous process ω(t, α) with independent increments, whose sample functions are bounded in the unit interval 0 ≤ t ≤ 1 for almost all α. If ω(t, α) is a process with independent increments, the characteristic function of ω(t, α) is of the form exp {tψ(u)} where where F is a σ-finite measure with finite mass outside every neighbourhood of o, and a and σ are constants. There is no essential restriction in supposing ω(0, α) = 0.

1. Introduction. Various types of multiple-valued dynamical systems have appeared in the literature over the past twenty years (2). The motivations for such generalizations are varied, but among others, control theory plays a significant role. In a recent paper (2), Bushaw has introduced an abstract approach which consolidates a broad class of these dynamical systems. The model is a quasi-ordered set (E, ρ); i.e. Ε is a non-empty set and ρ is a reflexive and transitive relation on E. E represents the ‘event’ space of some real-world system and ρ represents some class of ‘admissible’ inputs on the system; i.e. (e1, e2) ∈ ρ if and only if there is an admissible input function which ‘shifts’ the system from event e1 to event e2. ρ is called the attainability relation on E and the statement ‘ an event e2 is attainable from an event e1 ’ means that (e1, e2) ∈ ρ. Adopting the terminology of (2), we shall refer to the quasi-ordered set (E, ρ) as a polysystem.

In this paper certain Bessel type eigenfunction expansions are developed by considering a non-seif-adjoint problem which involves a radiation type condition

The differential equations governing the propagation of waves of electric and magnetic types in a plane stratified isotropic plasma are suitably generalized, and we investigate the possibility of models for which the moduli of the reflexion coefficients are identical for the two modes. First, the models are examined without the necessity of finding general solutions, and, secondly, by using the circuit relations for the hypergeometric functions occurring in the explicit solutions.

The calculus of 4-spinors, covariant with respect to arbitrary transformations in a 6-dimensional Riemann space, was presented earlier in a formulation analogous to the so-called ε-formalism in the 2-spinor calculus. Like the latter it is burdened by the appearance of a multiplicity of fractional spin weights and anti-weights as well as the arbitrariness of the trace of the linear spinor connexion. This paper deals in detail with a variant of the calculus which is more akin to the so-called γ-formalism in the 2-spirior calculus; and which is finally extended to be both gauge-invariant and phase-invariant.

A method of deriving the basis functions of the double-valued representations of a point group by the reduction of Kronecker products is described. The method has been used to derive expressions for these bases for cubic point groups for which the results are tabulated.

The inequalities related to Mill's Ratio were conjectured true by Birnbaum (2) and were proved by Murty (4) for sufficiently large x > 0. In the present paper, these are proved for all finite x and have been used to calculate an upper limit for Mill's Ratio over the range x > – 1.

An exact static solution of the system of Einstein–Maxwell field equations in the absence of charge is obtained when both the metric tensor gαβ and the Maxwell field tensor Fαβ exhibits plane symmetry in the sense that both remain invariant under the group of motions that characterize plane symmetry. Our solution generalizes the empty space-time solution with plane symmetry previously obtained by Taub to the situation when static charge-free electromagnetic fields are present. We hope to discuss non-static solutions of Einstein–Maxwell fields with plane symmetry as well as some other considerations in a subsequent paper.

The preferred-mode method of Roberts (11) is applied to the stability of liquid contained between coaxial cylinders, the inner of which is rotating. Accordingly the velocity field of a steady Taylor vortex is approximated by a truncated Fourier series and the steady state corresponding to a chosen wave number is obtained. The stability of a steady state so obtained is investigated:

(a) With respect to an axisymmetric perturbation associated with a Taylor vortex of a different axial wave number, so that a stable or ‘ preferred ’ steady state is determined. This is done for a narrow gap, η (the ratio of the radii of the cylinders) = 0·95, for Taylor numbers up to 40%, and for a wide gap, η = 0·5, up to 30% beyond the critical values.

(b) For a narrow gap, η = 0·95, with respect to a non-axisymmetric perturbation of a different axial wave number. The solutions obtained for the steady states are found to be stable to such perturbations for a range of Taylor numbers 40% beyond the critical value.

It is shown that given k samples of nj units from it is possible to construct simultaneous confidence intervals for two given linear functions of population means, (where cij are known constants), when population variances are not equal.

The method of steepest descents is widely used to find the asymptotic expansion of contour integrals of the form

where N is a large positive parameter, and f(z) and g(z) are analytic functions of z. (For the sake of simplicity it will here be supposed that f(z) and g(z) are regular except at ∞, but our arguments can be extended to include singularities at other points.) In the method of steepest descents the path of integration is deformed into a new equivalent path consisting of the paths of steepest descent through a and b, together with paths of steepest descent through certain saddle points, the relevant saddle points. (Paths of descent, etc., are defined in §1 below.) Watson's Lemma then shows that the complete asymptotic expansion depends on the local behaviour of f(z) and g(z) at the end-points and at the relevant saddle-points. On the other hand to determine which saddle-points are relevant is a global (non-local) problem and requires either the tracing of paths of steepest descent all the way from saddle-points and endpoints to ∞, or some other global process. It has often been noted that in applications of Watson's Lemma the paths of steepest descent can be replaced by a wider class of paths of descent. In this way we are led to global problems like the following: Given 2points z = α and z = β where Nf(a) > Nf(β), can apath of descent be drawn from α to β? If also Ff(α) = Ff(β), can a path of steepest descent be drawn from α to β?

Introduction. The problem of the scattering of high-frequency waves, which emanate from a line source in a homogeneous isotropic dielectric medium and impinge upon a cylindrical obstacle, has been attacked in a variety of ways. In certain cases, where both the shape of the obstacle and the conditions to be satisfied on its boundary are particularly convenient, an exact solution may be found by separation of the wave equation (see, for example, Marcuvitz (l)), but in general some form of approximation is necessary to obtain an explicit answer.

In (1) the velocity and magnetic fields were studied in the stagnation point region of a magnetized blunt body rotating with angular speed Ω. Some familiarity with this paper is assumed here: briefly, the nose section of the body was approximated by a disc of thickness t and conductivity σ′ and a perturbation solution was derived for small values of the diffusivity ratio ε (= ν/λ) and of the magnetic force coefficient N = σB2/4ρa. B is the uniform normal field component at the upperside (z = 0) of the disc, a is the strength of the external flow, p and σ are the density and conductivity of the fluid. The other two governing parameters are ω = Ω/a and β = σ′/σL, where L = (λ/a)½.

The paper deals with the free convection flow along a vertical plate moving arbitrarily in its own plane. The basic equations of the boundary-layer flow and heat transfer are linearized and the first two approximations are considered. The first approximation is the case of steady-state free convection flow while the second approximation is the response of the fluid velocity and temperature fields to the motion of the plate for which limiting solutions are obtained by the Laplace transform technique in two regions; namely, for large times and for small times. The particular case when the plate is given an impulsive start at t = 0 is investigated in detail. It is shown how the skin friction and the rate of heat transfer at the plate respond to the motion of the plate.

Solutions of the partial differential equation ψzzzz + ψx + 0 of the type ψ = x¼nw(y), where y = zx−¼ and n is an integer, are investigated. The equation occurs as a boundary-layer approximation in certain rotating and stratified fluid flows in which the production of vorticity (due, for example, to changes in the Coriolis parameter with latitude in two-dimensional flows on a beta plane, or by the buoyant generation of vorticity in a Boussinesq fluid) is opposed by a diffusive process. The similarity functions w(y) satisfy the fourth order differential equation

.

These functions have many properties analogous to those of error functions and parabolic cylinder functions. When n is a non-negative integer, there exist polynomial solutions of the latter equation. These have analogies with Hermite polynomials, although they do not form an orthogonal set in any useful sense. The main properties of the similarity functions are listed, including their series expansions, integral representations, asymptotic expansions and recurrence relations. In particular, a pair of independent solutions, Jon(y) and Kon(y), are denned such that Jon(y) and Kon(y) are real for real y and vanish at an exponential rate as y → + ∞. The function Jon(y) also decays exponentially as y → − ∞ if n is negative, and grows algebraically as y → − ∞ if n is positive. Curves of the functions Jon(y) and Kon(y) are given for |n| ≤ 3 and 0 < y < 6, and their more useful properties are listed.

In obtaining a solution of Laplace's equation in two dimensions by the method of conformal mapping, one first maps the points (x, y) of the Euclidean plane R2 into the algebra of complex numbers C by means of the real-linear function g: R2→C using the prescription g(x, y) = x + iy ≡ z. One then obtains solutions of Laplace's equation by allowing those mappings of C into itself that are expressed by analytic functions.

The problem of the propagation of time harmonic waves in an isotropic elastic half-space containing a submerged cylindrical cavity is solved analytically. Linear plane strain conditions are assumed. Using an expansion theorem proved in a previous paper (Gregory (3)), the elastic potentials are expanded in a series form which automatically satisfies the governing equations, the conditions of zero stress on the flat surface, and the radiation conditions at infinity. The conditions of prescribed normal and tangential stresses on the cavity walls are shown to lead to an infinite system of equations for the expansion coefficients. This system of equations is shown to be a regular L2-system of the second kind and from its unique l2-solution, the solution to the problem is constructed. The fundamental questions of existence and uniqueness are fully treated and methods are described for constructing the solution.

Three applications of the general theory are presented dealing respectively with the production, amplification and reflexion of Rayleigh waves.

The paper deals with the problem of investigating the effect of magneto-thermo-elastic interactions on the cooling process of an infinite circular cylinder when its boundary is subjected to a time-decaying temperature. The Hooke–Duhamel law of elasticity, the equation of heat conduction together with the electromagnetic equations of Maxwell supplemented by Ohm's law have been used to solve the problem. It is found that the Laplace transformation serves as an important tool for the solution of the problem.

It is shown that a cosmological model of light propagation associated with a uniformly expanding universe provides a physical significance to the hyperbolic velocity space by which this model can be described. Some implications of this result are discussed.