Stratifications et ensemble de non-cohérence d'un espace analytique réel

Sans résuméL'auteur est associé au groupe G.N.S.A.G.A. du C.N.R.     

A uniqueness result for a nonlinear hyperbolic equation

Summary We prove the uniqueness of the solution of a Cauchy problem for a nonlinear and non-local hyperbolic equation, which arises in a model of the dynamic of cardiac muscle.The authors were supported by G.N.A.F.A., G.N.I.M. and I.A.N. of C.N.R. and by M.P.I.     

Strongly distributive multiplicative hyperrings

The aim of this paper is to characterize the strongly distributive multiplicative hyperrings. A non trivial example is provided giving a model for such hyperrings; also a characterization theorem is proved.Dedicated to G. Tallini on the occasion of his 60^th birthday.Research supported by G.N.S.A.G.A. — C.N.R.     

Finite groups with Frobenius subgroup

Suppose the normalizer N of a subgroup A of a simple group G is a Frobenius group with kernel A, and the intersection of A with any other conjugate subgroup of G is trivial, and suppose, if A is elementary Abelian, that ¦a¦> 2n+1, where n=¦N:A¦. It is proved that if A has a complement B in G, then G acts doubly transitively on the set of right cosets of G modulo B, the subgroup B is maximal in G, and ¦B¦ is divisible by ¦a¦–1. The proof makes essential use of the coherence of a certain set of irreducible characters of N.Translated from Matematicheskie Zametki, Vol. 20, No. 2, pp. 177–186, August, 1976.The author would like to thank V. D. Mazurov for helpful discussions concerning the theorem proved in this note.     

Stabilité de la conjecture de Baum—Connes pour certains produits semi-directs de groupes

Let Γ = G ⋉_r N be the semi-direct product of two locally compact groups, and A a Y-algebra. We build a map from topological K-theory of Γ with coefficients in A to the one for G with coefficients in N ⋉_r A. For Γ a p-adic group equipped with a γ element and N an amenable group, we prove that Γ satisfies Baum-Connes conjecture with coefficients when G does.     

Anelli ternari di Hestenes primitivi,con ideale destro minimale

Summary In this paper I classify primitive Hestenes ternary rings having minimal onesided ideals.

---

---

L'autore appartiene al G.N.S.A.G.A. del C.N.R.     

On finite groups with a reducible permutability-graph

We characterize finite groups in which the permutability-graph has more than one connected component.Research partially supported by G.N.S.A.G.A. of C.N.R. and M.U.R.S.T. of Italy.     

Essential coverings and triangulations

Sunto In questo lavoro si danno condizioni sufficienti per un ricoprimento di una varietà differenziabile V affinchè il suo nerbo abbia lo stesso tipo P.L. di V e si prova l'esistenza di una larga classe di siffatti ricoprimenti.

---

---

The author is member of G.N.S.A.G.A. of the C.N.R. and partially supported by a N.A.T.O.-C.N.R. fellowship.     

Derived semifield planes with affine elations

Derived semifield planes admitting non trivial affine elations with more than one centre are examined in detail and several new examples of such plantes are constructed. A new characterization of the Hall planes of even order among derived semifield planes is also given.Research partially supported by G.N.S.A.G.A. (C.N.R.)     

Functions of bounded characteristic in n-connected domains

In this paper we define a metric d on the Nevanlinna class N(G) of an n-connected domain G. We show that (N, d) is a complete translation invariant metric space in which multiplication by a constant is not continuous. We also show that N(G) is disconnected. Our main theorem characterizes the component of the origin of N(G), extending earlier work of J. Shapiro and A. Shields and of J. Roberts for the unit disk. We use the factorization theorem of R. Coifman and G. Weiss to show that the component of the origin of N(G) is equal to the set of all functions f in N(G) for which the positive part of the singular measure of the least harmonic majorant of log ¦f¦ is continuous.     

关于Glauberman-Isaacs特征标对映的注记

假设群A经自同构互素地作用在G上.设χ是G的一个A-不变不可约特征标,π(G,A)表示Glauberman-Isaacs特征标对映.对于B≤A,T.R.Wolf曾猜想χπ(G,A)是χπ(G,B)a的一个不可约成份,此处C=CG(A).设G=N(X)H且(|N|,|H|)=1,假定H是A-不变的且N是一个Sylow塔群,N的Sylow-子群是交换的.在本文中,我们证明了如果这个猜想对所有H的A-不变子群成立,则猜想对G也成立.     

A note on a Heegaard diagram of S3

In this work, we study via crystallizations some properties of the counterexample to the Whitehead's conjecture and to the algorithm of Volodin-Kuznetsov-Fomenko, introduced by Ochiai. Research performed under the auspices of the G.N.S.A.G.A.-C.N.R., and within the Project “Topologia e geometria”, supported by M.U.R.S.T. of Italy     

n2-sets in a projective plane which determine exactly n2+n lines

In this paper n²-sets, in a projective plane, determining exactly n²+n lines are completely characterized.Research partially supported by G.N.S.A.G.A. (C.N.R.).Paper written while the second author was at the University of Rome supported by a grant within the Italian Hungarian cultural exchange program.     

Some new examples of flocks of Q+(3,q)

Three new examples of non-linear flocks of the non-singular ruled quadric Q⁺(3,q) of PG(3,q) are given.This paper was written while the author was a member of G.N.S.A.G.A. of C.N.R., with partial financial support from M.P.I.     

Una classe di algebre rigide

Riassunto Si prova la rigidità di una certa classe di algebre integre di Cohen-Macaulay.

---

Summary We prove the rigidity of a certain class of algebras which are Cohen-Macaulay integral domains.

---

---

Lavoro svolto nell'ambito del G.N.S.A.G.A., sez. n. 3, del C.N.R.     

Quaternionic differential forms and symplectic Pontrjagin classes

Sunto Si considerano fibrati vettoriali quaternionali dotati di connessione quaternionale e si determinano forme differenziali rappresentanti delle classi simplettiche di Pontrjagin.

---

---

Lavoro eseguito nell'ambito del gruppo G.N.S.A.G.A. del C.N.R.; esposto in una comunicazione a Oberwolfach, 7–13 Giugno 1981.     

Sul problema di Dirichlet in un cono diR n inL p

Summary This work is concerned with Dirichlet boundary-value problem for the equation (1) in a cone G di Rⁿ. This problem is investigated in Sobolev weight spaces W _r,p ^s (G): existence and uniqueness theorem si given.

---

---

Entrata in Redazione il 5 dicembre 1977.

---

Lavoro eseguito nell'ambito del G.N.A.F.A. del C.N.R.     

Inverse Near Permutation Semigroups

A transformation semigroup over a set X with N elements is said to be a near permutation semigroup if it is generated by a group G of permutations on N elements and by a set H of transformations of rank N - 1. In this paper we give necessary and sufficient conditions for a near permutation semigroup S = ‹G,H›, where H is a group, to be inverse. Moreover, we obtain conditions which guarantee that its semilattice of idempotents is generated by the idempotents of S of rank greater than N - 2 or N - 3.     

On the geometry of quadrics and their degenerations

members of G.N.S.A.G.A. of C.N.R.