模的嵌入问题

本文首先在文［１］工作的基础上进一步讨论了“每个有限生成模可嵌入到自由模”的环类，这类环称为ＦＧＦ－环，接着引进了一类包括ＦＧＦ－环和拟完全环的环类，这类环称作ＦＧＦＦ－环，即“每个有限生成平坦模可嵌入到自由模中”，讨论了这类环的一些特征性质及其与已知一些重要环类间的关系．这一类环的背景是文［１－６］．本文还回答了文［５］的一个问题．     

关于分次环的分次性质和非分次性质

本文证明了对有限群分次环Ｒ而言,下列条件等价：（１）Ｒ是左ｇｒ－自内射环（左ｇｒ－ＰＦ环,左ｇｒ－ＱＦ环,左ｇｒ－线性紧环）．（２）Ｒ是左自内射环（左ＰＦ环,左ＱＦ环,左线性紧环）．（３）Ｒ＃Ｇ^*是左自内射环（左ＰＦ环,左ＱＦ环,左线性紧环）．     

拟完备环与FC—环的注记

设Ｒ是有单位元的环，Ｓ是Ｒ的几乎优越扩雍，Ｇ是有限群且｜Ｇ＾｜＾－１∈Ｒ，证明了Ｒ是ＦＣ－环当且仅当Ｓ是ＦＣ－环，也当且仅当Ｓｍａｃｈ积Ｒ＃Ｇ是ＦＣ－环。     

关于SF—环的几点注记

文中，我们证明了如下主要结果：Ⅰ对于环Ｒ，下面条件是等价的：（１）Ｒ是Ａｒｔｉｎ半单环；（２）Ｒ是左ＳＦ－环，且Ｒ满足特殊右零化子降链条件；（３）Ｒ是左ＳＦ－环和Ⅰ－环，且Ｒ＾Ｒ具有有限Ｇｏｌｄｉｅ维数。Ⅱ对于环Ｒ，下面条件是等价：（１）Ｒ是Ｖｏｎ Ｎｅｕｍａｎｎ正则环；（２）Ｒ是左ＳＦ－环，且每个奇异循环左Ｒ－模的极大子模是平坦的。     

REMARKS ON QUASI-PERFECT RINGS AND FC-RINGS

设Ｒ是有单位元的环，Ｓ是Ｒ的几乎优越扩张，Ｇ是有限群且｜Ｇ｜－１∈Ｒ．证明了Ｒ是ＦＣ－环（拟完备环，凝聚环）当且仅当Ｓ是ＦＣ－环（拟完备环，凝聚环），也当且仅当Ｓｍａｃｈ积Ｒ＃Ｇ＊是ＦＣ－环（拟完备环，凝聚环）．     

右IF－环及凝聚环的挠理论

本文研究了右ＩＦ－环的性质，证明出环Ｒ是右ＩＦ－环当且仅当Ｒ是左凝聚环，并且是平坦模；由此证明出右ＩＦ－环与左ＧＱＦ－环是等价的，其次应用右ＩＦ－环研究了凝聚环的挠理论性质，证明出凝聚环与Ｔ－凝聚环的关系。     

凝聚环和IF环

本文利用特征模，Ｎ０－内射维数对凝聚环给出了一些新的刻划．得到了凝聚环与ＩＦ环的一些有意义的性质．推广了引文［１］中的两个主要定理之一的定理２的结论．     

右IF－环及凝聚环的挠理论

本文研究了右ＩＦ－环的性质，证明出环Ｒ是右ＩＦ－环当且仅当Ｒ是左凝聚环，并且是平坦模；由此证明出右ＩＦ－环与左ＧＱＦ－环是等价的，其次应用右ＩＦ－环研究了凝聚环的挠理论性质，证明出凝聚环与Ｔ－凝聚环的关系。     

关于SF－环的几点注记

本文中，我们证明了如下主要结果：Ⅰ　对于环Ｒ，下面条件是等价的：（１）Ｒ是Ａｒｔｉｎ半单环；（２）Ｒ是左ＳＦ－环，且Ｒ满足特殊右零化于降链条件；（３）Ｒ是左ＳＦ－环和Ｉ－环，且Ｒ￣Ｒ具有有限Ｇｏｌｄｉｅ维数。Ⅱ对于环Ｒ，下面条件是等价的：（１）Ｒ是ＶｏｎＮｅｕｍａｎｎ正则环；（２）Ｒ是左ＳＦ－环，且每个苛异循环左Ｒ－模的极大子模是平坦的。     

gr—正则环和矩阵环的gr—正则性

本文主要证明了（１）当Ｇ是有限群时，Ｇ－型分次环Ｒ是ｇｒ－正则的当且仅当Ｒ＃Ｇ是正则的当且仅当ＭＧ（Ｒ）是ｇｒ－正则的当且仅当对每个λ∈Ｇ和Ｇ的任意非空子集Ｈ和Ｆ，ＭＨ×Ｆ（Ｒ）的每个矩阵都有１－逆。（２）当Ｇ是任意群，Ｇ－型分次环Ｒ是反ｇｒ－正则的当且仅当Ｆ（Ｒ＃Ｇ）是反正则的当且仅当对每个λ∈Ｇ和Ｇ的任意非空子集Ｈ和Ｋ，ＦＭＨ×Ｆ（Ｒ）的每个矩阵有２－逆当且仅当ＦＭＧ（Ｒ）是ｇｒ－反正则的。     

Monoides de comptage et langages rationnels

We study some syntactic properties of languages obtained from rational languages through counting operations. These counting operations use the congruences-threshold p, modulo n—on the set of integers. We show that in some cases they preserve the properties of syntactic monoids: the structure of idempotent and commutative monoids is not modified, aperiodic monoids with central idempotents keep their central idempotents and their regular D-classes still are groups although not trivial, aperiodic left (right) nilsimple semigroups still have regular R (L)-classes which are (non trivial) groups. If possible results are expressed in terms of varieties of semigroups or monoids.     

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.)     

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.     

A (3+1)‐dimensional Painlevé integrable model obtained by deformation

To find some non‐trivial higher‐dimensional integrable models (especially in (3+1) dimensions) is one of the most important problems in non‐linear physics. An efficient deformation method to obtain higher‐dimensional integrable models is proposed. Starting from (2+1)‐dimensional linear wave equation, a (3+1)‐dimensional non‐trivial non‐linear equation is obtained by using a non‐invertible deformation relation. Further, the Painlevé integrability of the resulting model is also proved. Copyright © 2002 John Wiley & Sons, Ltd.     

Existence of one non‐trivial anti‐periodic solution for second‐order impulsive differential inclusions

The existence of one non‐trivial solution for a second‐order impulsive differential inclusion is established. More precisely, a recent critical point result is exploited, in order to prove the existence of a determined open interval of positive eigenvalues for which the considered problem admits at least one non‐trivial anti‐periodic solution. Copyright © 2017 John Wiley & Sons, Ltd.     

分子格上伪补的构造

本文给出了分子格上伪补的构造定理，并证明了当一个非平凡分子格上有伪补，其既约因子上并不一定存在伪补，但其准既约因子上一定存在伪补，且任一分子格上的伪补都可表为其准既约因子上伪补的直积．     

Un problema al contorno per una classe di operatori ellittico-parabolici di ordine2m

Summary In this paper, boundary-value problems for degenerate elliptic parabolic operators of order 2m are discussed. An existence theorem is proved, with the help of a non trivial induction argument (substantially, with respect to the order of certain derivatives) and of a ? small parameter-method ?.

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Entrata in Redazione il 28 novembre 1973.

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Lavoro eseguito con contributo del C.N.R. nell'ambito del Gruppo di Ricerca per l'Analisi Funzionale.     

Grafici minimi completi

Riassunto Si riconsidera il problema della esistenza di soluzioni della equazione delle superficie minime su tutto lo spazio. Si presenta un metodo che, con ulteriori studi, potrebbe portare ad associare ad ogni cono minimo singolare una soluzione della equazione delle superficie minime su tutto lo spazio, intendendo che a coni diversi sono associate soluzioni diverse. è sottinteso che parliamo sempre di soluzioni non banali, cioè non lineari.

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Summary We reconsider the problem of the existence of non trivial solutions for the minimal surface equation in the whole space. We present a method which might lead to the proof of the existence of a non trivial solution for the minimal surface equation in the whole space for each singular minimal cone.

     

A decomposition theorem for lie algebra bundles

We prove thata locally trivial Lie algebra bundle is a semidirect product of its radical bundle and a semisimple bundle by using thecohomological methods.A simple bundle which is not semisimple is given and it is also an example of a non locally trivial bundle for which such a decomposition fails.     

Beispiele endlicher und unendlicher K-Loops

In this note examples are given for non trivial K-loops. There are commutative examples as well as non commuative, finite examples as well as infinite. Furthermore it will be shown that under an additional condition K-loops and Brück loops coincide.