Suppose that H/N is a section of a finite group G, i.e., that H is a subgroup of G and N is a normal subgroup of H. We are interested in the existence of normal subgroups M of G satisfying: Such an M can be called a normal complement to the section H/N in G.

This paper shows that every lattice group G can be densely embedded in a unique laterally complete lattice group H (the lateral completion of G). All reasonable structure properties of G are inherited by H and we have the following relationships between the ideal radical L(G), the distributive radical D(G) and the radical R(G) of G and the corresponding radicals of H. .

Let G be a finite P-group. Denote dim H1 (G, Zp) by d(G) and dimH2(G, Zp) by r(G), then d(G) is the minimal number of generators of G and G has a presentation where F is free on x1, …, xd(G) and R is the normal closure in F of R1, …, Rm. We have always that m ≧ r(G) = d(R/[F, R]) and we say that G belongs to a class, Gp, of the finite pgroups if m = r(G). It is well known (see for example Johnson and Wamsley (1970)) that if G and H are finite p-groups then r(G x H) = r(G) + r(H) + d(G)d(H) and hence G, H∈Gp implies Gx H∈Gp, also it is shown in Wamsley (1972) that if G is any finite pgroup then there exists an H∈Gp such that G x H belongs to Gp. Let G1 = G and Gk = Gk-1 x G then we show in this note that if G is any finite p-group, there exists an integer n(G), such that Gk∈Gp for alal k ≧ n(G).

An immune set is found such that the recursive equivalence type of its infinite subsets are universal in a very strong sense.

Let G be a finitely presented group. A finite presentation P of G is said to have defiency m – n if it defines G with m generators and n relations. The deficiency of G is the maximum of the deficiencies of all the finite presentations P of G. If G is finite the deficiency of G is less than or equal to zero. The only finite two generator groups of deficiency zero that are known are certain metacyclic groups given by Wamsley (1970), a class of nilpotent groups given by Macdonald in (1962) and a class of groups given by Wamsley (1972).

Let R, C be the additive groups of the real, complex numbers respectively. Using the Axiom of Choice (A.C.), these groups may be shown to be isomorphic. We show that this cannot be proved in Zermelo-Fraenkel set theory (see e.g. Fraenkel, Bar-Hillel and Levy (1973)) without the additional assumption of A.C. This is one of the most “concrete” used of the Axiom of Choice of which I know. THEOREM 1 (assuming (A.C)). C ≅ R.

In this note we give an example of a homotopy commutative H-space X that is not dominated by any homotopy associative, homotopy commutative H-space. In particular, X is not dominated by Ω2S2X.

In this paper the problem of constructing an arc of minimum length joining two fixed points: P1, P2, in an arbitrary subset: S, of a metric space is considered. The approach taken is a departure from the classical methods of the calculus of variations in that it is topological character, making use of the properties of sets rather than differential calculus.

A mapping κ: P(X) → P(X) is a quasi-closure operator (see Thron (1966) page 44) if (i) □κ = □, and for all A, B ∈ P(X) we have (ii) A ⊆ Aκ, and (iii) (A ⋓ B)κ = Aκ ∪ Bκ one easily deduces that such operators have the further property: (iv) if A ⊆ B ⊆ X, then Aκ if κ also satisfies: (v) Aκ2 ⊆ Aκ for all A ⊆ X, then κ is called a Kuratowski closure operator.

The purpose of this paper is to present three somewhat disparate results on free objects in three different classes of λ-groups. The first is that no proper ideal of a finitely generated free vector lattice can itself be a free vector lattice. Second, each free abelian lgroup is characteristically simple. The third result is that each disjoint subset of a free (non-abelian) lgroup is countable.

Let G be a group of order 2n and x, y ∈ G. We define the Commutator [x, y] as x−1y−1xy. Similarly, if X, Y are subsets of G, then [X, Y] denotes the sub-group genrated by all commutators of the form [x, y] where x ∈ X, y ∈ Y. Using this, we may define the lower central series of G inductively by The following results are well known.

If Do, D1, … are linear maps from an algebra A to an algebra B, both over the complexes, then {Do, D1, …} is a system of derivations if for all a, b in A and for all nonnegative integers k, we have Where C(k, i) is the binomial coefficient k!/i! (k—i)!. By (1.1) we see that Do must be a homomorphism and in case Do = I, where I is the identity map, D1 is a derivation and, for k ≧ 2, the Dk are higher derivations in the sense of Jacobson (1964), page 191. Gulick (1970), Theorem 4.2, proved that if A is a commutative regular semi-simple F-algebra with identity and {DO, D1, …} is a system of derivations from A to B = C(S(A)), the algebra of all continuous functions on the spectrum of A, where Dox = x, then the Dk are all continuous. Carpenter (1971), Theorem 5, shows that the regularity condition is unnecessary and Loy (1973) generalizes this a bit further. One of the many interesting features of systems of derivations is that they help determine analytic structure in Banach algebras (see for example, Miller (to appear)).

Let {Xt}t ∈ T be a family of real (R) random variable defined on a probability space (Ω, A P) and having the ranges in a subset S of R, that is, Xt (Ω) ⊂ S for all t. Let X be the mapping of Ω into the function space St such that for any ω ∈ Ω We shall write X = {Xt}t ∈ T and call X the random fundtion arising from {Xt}t ∈ T. It is well-known that any finite subfamily of {Xt}t∈T induces a “finite joint distribution” in ST, and according to Kolmogorov (1933) these finite joint distributions can be simultaneously extended to a probability measure Po on the Borel class Bo of subsets of ST. This extension is natural in the sense that for any B∈B0P0(B) turns out to be exactly P[X−1(B)]. The Kolmogorov extension Po has however a shortcoming in that its domain B0 is not broad enough to include many events of practical interest.

The theory of Yang-Mills fields is explicity formulated in terms of the theory of connections in principal and associated fiber bundles. Special attention is paid to the fiber bundles with Lorentz and Poincaré structures. Equations of the form ∇ψ = 0, where ∇ is a generalized convariant derivative, are shown to contain “mass” terms if the connection in the Poincaré fiber bundle is cononically associated to the connection in the Lorentz fiber bundle.

Theorem 6 of Wilde (1971) is in error. Følner's condition is necessary, but not sufficient, for amenability of a τ-semigroup. For clearly sufficiency would imply that every finite τ-semigroup is amenable, and the simple example on p. 503 of Wilde (1971) shows that this is not so. We refer the reader to Namioka (1964) for a lucid explanation of the fundamental ideas involved.