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In the short sketch which I propose to give of the History of Mathematics in Scotland up to the end of the 18th century I must limit myself mainly to the work of the Universities. An adequate treatment of the subject would involve considerations of a general educational character that would range over the relations of the school to the University, the distribution of the various subjects of study and the place of mathematics in the educational system; but it is, of course, impossible to undertake such an extensive investigation at present, though it seems to me that an investigation, with special reference to mathematics, is greatly needed and might form the subject of a research that would be of real value as a contribution to the development of educational ideas. It would be improper, however, to omit all reference to school mathematics, since the school conditions determine, to a considerable extent, those of the University, as current discussions in Scotland clearly show, even though a sound appreciation of the relations between school and University may at times be lacking.
On p. 403 of Greenhill's Calculus (2nd Ed.) the following sentence occurs:— “By differentiation of the integral
with respect to A, B, or C we can deduce the results of
For the evaluation of tlie typical form in which f(x) is a linear function, especially when A, B, etc., are given numbers, the method of differentiation does not seem very suitable; be that as it may, it may perhaps be of some interest to investigate a formula of reduction analogous to those in use for the integrals in which Ax2 + 2Bx + C is replaced by a linear function and f(x) is a constant.
An equation is derived for the strains of an arbitrary elastic field in an infinite matrix perturbed by several inclusions. The equation is solved exactly when the shear moduli of the inclusions and matrix are identical, and also when only a single ellipsoidal inclusion perturbs a field uniform at infinity. Mean-values of the strains are then calculated for non-uniform fields perturbed either by an ellipsoid or by a system of weakly-interacting spheres.
Over a field of characteristic p>0 the group algebra of a finite group has a unique maximal nilpotent ideal, the Jacobson radical of the algebra. The powers of the radical form a decreasing and ultimately vanishing series of ideals and it would be of interest to determine the least vanishing power. Apart from the work of Jennings (3) on p-groups little is known in general (cf. (5)) about this particular power of the radical (cf. Remarks of Brauer in (4), p. 144. Problem 15). In this paper we give non-trivial lower bounds for the index of the least vanishing power of the radical when the group is p-soluble. Of the lower bounds we give we show that that lower bound, which is dependent solely on the order of the group, is the best possible such bound and that this bound is invalid if the assumption of p-solubility is omitted.
Banach modules over C*-algebras (von Neumann algebras) that can be represented isometrically as operator modules (normal operator modules, respectively) are characterised.
Theorem. A compact, orientable, Riemannian manifold Mn, with positive definite metric and zero Ricci curvature, is flat if the first Betti number R1 exceeds n — 4.
In this statement of the theorem it is assumed that the dimensions of Mn are not less than four. If this is not the case, the result is still valid but appears as a purely local result and is true for a metric of arbitrary signature.
Two n-planes Γ and Δ in real Euclidean r-space Rr are called isoclinic with parameter λ if the angle θ between any x in Γ and its orthogonal projection Px on Δ is unique, with cos2 θ = λ. Let vλ(n, r) denote the maximum number of equi-isoclinic (i.e. pairwise isoclinic) n-planes in Rr with parameter λ.
The following algebra possesses certain points of interest and is, I think, worth putting on record; it includes the algebra of matrices as a special case. Consider the algebra H over a ring F defined by
where hpq(p, q = 1, 2, …., n) are linearly independent over F. If are any elements of H, then from (1)
A geometric hypothesis is presented under which the cohomology of a group G given by generators and defining relators can be computed in terms of a group H defined by a subpresentation. In the presence of this hypothesis, which is framed in terms of spherical pictures, one has that H is naturally embedded in G, and that the finite subgroups of G are determined by those of H. Practical criteria for the hypothesis to hold are given. The theory is applied to give simple proofs of results of Collins-Perraud and of Kanevskiĭ. In addition, we consider in detail the situation where G is obtained from H by adjoining a single new generator x and a single defining relator of the form xaxbxεc, where a, b, c ∈ H and |ε| = 1.
Let $G$ be a locally compact group, $A$ a continuous trace $C^*$-algebra, and $\alpha$ a pointwise unitary action of $G$ on $A$. It is a result of Olesen and Raeburn that if $A$ is separable and $G$ is second countable, then the crossed product $A\times_\alpha G$ has continuous trace. We present a new and much more elementary proof of this fact. Moreover, we do not even need the separability assumptions made on $A$ and $G$.