一个数论函数的均值

研究了三进制中数字和函数的均值性质，给出了一般情况下均值A1(N)，A2(N)，A3(N)的求和公式．     

On the geometry of quadrics and their degenerations

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

弱闭T(N)-模的预零化子的等距映射

本文刻划了弱闭T(N)-模的预零化子间的等距映射.设u,W分别为由左连续序同态N→~N和N→~N所确定的弱闭T(N)-模, u(?),W(?)分别为u,W的预零化子,Φ为由u(?)到W(?)上的线性等距映射.若(0)*=(0)#=(0),dim(0)+≠1且min{dim(H(?)~H),dim(He(?)^H)}≥2,则存在酉算子Ui,Vi(i=1,2),使得Φ(A)=U1AV*1或Φ(A)=U2A*V2*.     

On the greatest prime factor of integers of the form ab + 1

Let N be a positive integer and let A and B be dense subsets of {1,...,N }. The purpose of this paper is to establish a good lower bound for the greatest prime factor of ab + 1as a and b run over the elements of A and B respectively.     

On the structure of partition which the difference of their representation function is a constant

Periodica Mathematica Hungarica - Let $$\mathbb {N}$$ be the set of nonnegative integers. For any set $$A \subset \mathbb {N}$$ , let $$R_1(A, n)$$ , $$R_2(A, n)$$ and $$R_3(A, n)$$ be the number...     

Free boundary problems in the theory of fluid flow through porous media: Existence and uniqueness theorems

Summary Elliptic free boundary problems in the theory of fluid flow through porous media are studied by a new method, which reduces the problems to variational inequalities: existence and uniqueness theorems are proved. Entrata in Redazione il 3 agosto 1972. Research supported by C.N.R. in the frame of the collaboration between L.A.N. of Pavia and E.R.A. 215 of C.N.R.S. and of Paris University. ? Laboratorio di Analisi Numerica del C.N.R. di Pavia ? and ? Università di Pavia ?. ? Università di Pavia ? and ? G.N.A.F.A. del C.N.R. ?.     

On the Generalized Strongly Nil-Clean Property of Matrix Rings

Let R be an associative unital ring and not necessarily commutative.We analyze conditions under which every n × n matrix A over R is expressible as a sum A =E1 +…+ Es + N of (commuting) idempotent matrices Ei and a nilpotent matrix N.     

Numerical semigroups bounded by the translation of a plane monoid

Aequationes mathematicae - Let $$\mathbb {N}$$ be the set of nonnegative integer numbers. A plane monoid is a submonoid of $$(\mathbb {N}^2,+)$$ . Let M be a plane monoid and $$p,q\in \mathbb {N}$$...     

On the maximum genus of some graphs with upper imbeddable subgraphs

In this paper we will consider some properties of the maximum genus of those graphs which decompose into upper imbeddable subgraphs, any two of which have at most one vertex in common.With 1 FigureLavoro eseguito nell'ambito del G.N.S.A.G.A. del C.N.R.     

一个素数和一个素数的平方和问题

H表示一个正整数N的集合,使对任意的正整数q,同余方程a+b~2≡N(mod q)在模q的既约剩余系中有解a;b.E(x)表示N≤x,N∈H,但不能表成p_1+p_2~2=N的数的个数,其中p_1,p_2个表示素数,则E(x)<相似文献   

Stability of the periodic motions of autonomous systems with lag

In the article we give a generalization of the theorem of A. A. Andronov and A. A. Vitt on the stability of the periodic motions of autonomous systems described by ordinary differential equations to autonomous time-lag systems. The investigation is based on the procedures developed by N. N. Krasovskii which consider the differential equations with lag in a functional space of continuous functions. There is a bibliography of eight items.Translated from Matematicheskie Zametki, Vol. 2, No. 5, pp.561–568, November, 1967.     

On the Topological Stable Rank of a Noncommutative Version of the Disc Algebra

Based on a bounded approximate version of LU decomposition, we calculate the topological stable rank of \({{\mathcal {A}}}_{{\mathcal {N}}}\), which is a noncommutative version of the disc algebra. In addition, a general characterization of the maximal two-sided ideals of \({{\mathcal {A}}}_{{\mathcal {N}}}\) will be obtained.     

A note on the amenable subgroups of PSL (2,R)

In this note we give a characterization of the amenable subgroups of PSL (2,R) in terms of the action on the hyperbolic half-plane.This work was partially supported by G.N.A.F.A. of the C.N.R., Italy.     

On the Griffiths group of the cubic sevenfold

Partially supported by Science Project Geometry of Algebraic Varieties, n. 0-198-SC1, and by fundings from M.U.R.S.T. and G.N.S.A.G.A. (C.N.R.), Italy     

Some remarks on the mollification of piecewise-linear homeomorphisms

We construct an example of a piecewise positive (a.e.) Jacobian such that the usual convolution does not preserve the sign of the Jacobian. Bibliography:4 titles. Dedicated to N. N. Uraltseva on her jubilee Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 221, 1995, pp. 235–243. Translated by G. A. Seregin and T. N. Shilkin.     

基于有限集[N]上相交关系构作的二元等重码

对于自然数s,r,k,N,0相似文献   

Probabilistic aspects of the relationships between the discrete kinetic theory and lattice model

A general procedure for the construction of a spatial lattice model related with a general discrete velocity model is derived. Explicit relations for the 6, 8 and 14 discrete models are stated.

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Riassunto Si ricava, nell'ambito della teoria cinetica discreta, un procedimento generale per la costruzione di un modello al lattice spaziale. Si stabiliscono relazioni esplicite per i modelli a 6, 8 e 14 velocità.

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This work is partially supported by C.N.R.-G.N.F.M. project PS IPPMI of C.N.R.-G.N.F.M. and by the Minister for the Scientific Research.     

Classification of Special Anosov Endomorphisms of Nil-manifolds

In this paper we give a classification of special endomorphisms of nil-manifolds:Let f:N/Γ → N/Γ be a covering map of a nil-manifold and denote by A:N/Γ → N/Γ the nil-endomorphism which is homotopic to f. If f is a special T A-map, then A is a hyperbolic nil-endomorphism and f is topologically conjugate to A.