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1.
Keith A. Kearnes 《Algebra Universalis》2001,46(3):373-387
We show that a locally finite variety is congruence join semidistributive if and only if it satisfies a congruence identity
that is strong enough to force join semidistributivity in any lattice.
Received February 9, 2000; accepted in final form November 23, 2000. 相似文献
2.
Manuel Abad Juan Manuel Cornejo Patricio Díaz Varela 《Mathematical Logic Quarterly》2012,58(3):168-176
In this paper we prove that the free algebras in a subvariety $\mathcal V$ of the variety $\mathcal {SH}$ of semi‐Heyting algebras are directly decomposable if and only if $\mathcal V$ satisfies the Stone identity. 相似文献
3.
Keith A. Kearnes Á gnes Szendrei 《Transactions of the American Mathematical Society》1997,349(5):1749-1768
In this paper we describe a one-variable Mal'cev-like condition satisfied by any locally finite minimal variety. We prove that a locally finite variety is minimal if and only if it satisfies this Mal'cev-like condition and it is generated by a strictly simple algebra which is nonabelian or has a trivial subalgebra. Our arguments show that the strictly simple generator of a minimal locally finite variety is unique, it is projective and it embeds into every member of the variety. We give a new proof of the structure theorem for strictly simple abelian algebras that generate minimal varieties.
4.
It is proved that every variety satisfying the Congruence Intersection Property (CIP) is Abelian. In addition, a CM Abelian
variety has the CIP if and only if it has a constant term operation. Finally, a CM variety is Abelian if and only if it has
the weak CIP.
Received October 8, 1998; accepted in final form January 5, 1999. 相似文献
5.
6.
Alessandro Veneruso 《Monatshefte für Mathematik》2000,130(3):231-252
Let be the Heisenberg group of dimension . Let be the partial sub-Laplacians on and T the central element of the Lie algebra of . For any we prove that the operator is bounded on the Hardy spaces , if the function m satisfies a Hrmander-type condition on which depends on . We also obtain analogous results for the operators and , where the function m satisfies analogous H?rmander-type conditions on and on , respectively. Here is the Kohn-Laplacian on .
(Received 28 July 1999; in final form 6 March 2000) 相似文献
7.
For an arbitrary lattice identity implying modularity (or at least congruence
modularity) a Maltsev condition is given such that the identity holds in congruence lattices
of algebras of a variety if and only if the variety satisfies the corresponding Maltsev
condition. 相似文献
8.
Elena Rubei 《manuscripta mathematica》2002,108(1):135-137
We exhibit an example of a line bundle M on a smooth complex projective variety Y s.t. M satisfies Property N
10
, the 10-module of a minimal resolution of the ideal of the embedding of Y by M is nonzero and M
2
does not satisfy Property N
10
. Thus this is a completely convincing example showing that surprisingly it is not true that if a line bundle M satisfies Property N
p
then any power of M satisfies Property N
p
. We recall that in [Ru] we proved the following statement: if M is a line bundle on a smooth complex projective variety and M satisfies Property N
p
then M
s
satisfies Property N
p
if s≥p.
Received: 5 March 2001 相似文献
9.
We prove that if A is a finite algebra with a parallelogram term that satisfies the split centralizer condition, then A is dualizable. This yields yet another proof of the dualizability of any finite algebra with a near unanimity term, but more importantly proves that every finite module, group or ring in a residually small variety is dualizable. 相似文献
10.
W. Bentz 《Algebra Universalis》1999,42(1-2):9-16
In 1997, Coleman showed that a variety V is n-permutable for some n iff every T
0-topological Algebra in V is T
1. Here we show that the implication " sober" is another such characterization for n-permutability. Other implications of a similar nature are given. For example, an n-permutable variety having a majority term satisfies ".
Received July 13, 1998; accepted in final form April 13, 1999 相似文献
11.
In this article, we introduce the new notion of acyclic improper colorings of graphs. An improper coloring of a graph is a vertex-coloring in which adjacent vertices are allowed to have the same color, but each color class Vi satisfies some condition depending on i. Such a coloring is acyclic if there are no alternating 2-colored cycles. We prove that every outerplanar graph can be acyclically 2-colored in such a way that each monochromatic subgraph has degree at most five and that this result is best possible. For planar graphs, we prove some negative results and state some open problems. © 1999 John Wiley & Sons, Inc. J Graph Theory 32: 97–107, 1999 相似文献
12.
Elena Rubei 《manuscripta mathematica》2000,101(4):449-455
Let M be a very ample line bundle on a smooth complex projective variety Y and let ϕ
M
:Y→P(H
0(Y, M)*) be the map associated to M; we are concerned with the problem to see whether the syzygies of ϕ
M
(Y) give information on the syzygies of ϕ
M
s
(Y). In particular we prove that if Y is a smooth complex projective variety and M is a line bundle on Y satisfying Property
N
p
, then M
s
satisfies Property N
p
if s≥p.
Received: 11 June 1999 / Revised version: 22 November 1999 相似文献
13.
Euisung Park 《Journal of Pure and Applied Algebra》2007,211(1):15-23
In this paper we study defining equations and syzygies among them of projective bundles. We prove that for a given p≥0, if a vector bundle on a smooth complex projective variety is sufficiently ample, then the embedding given by the tautological line bundle satisfies property Np. 相似文献
14.
The main result in this paper states that if a one-parameter Gaussian process has C
2k
paths and satisfies a non-degeneracy condition, then the distribution of its maximum on a compact interval is of class C
k
. The methods leading to this theorem permit also to give bounds on the successive derivatives of the distribution of the
maximum and to study their asymptotic behaviour as the level tends to infinity.
Received: 14 May 1999 / Revised version: 18 October 1999 / Published online: 14 December 2000 相似文献
15.
利用图的完形刻画wsr1条件 总被引:1,自引:0,他引:1
本文证明了:对于拟投射右R-模M,EndR(M)满足wsr1条件(即弱的stable range one条件)当且仅当MR是T-投射模;wsr1条件是左右对称的;对于von Neumann正则环R,R满足wsr1条件当且仅当R为单侧幺正则环. 相似文献
16.
本文研究模的弱消去问题和exchange环的弱稳定条件,给出了wsrl条件的新刻划,证明了对具有有限exchange性质的模,外弱消去等价于内弱消去并等价于自同态环满足wsrl条件. 相似文献
17.
A Euclidean complex X is a simplicial complex whose simplices are (flat) Euclidean simplices. We construct a natural Brownian motion on X and show that if X has nonpositive curvature and satisfies Gromov's hyperbolicity condition, then, with probability one, Brownian motion tends
to a random limit on the Gromov boundary. Applying a combination of geometric and probabilistic techniques we describe spaces
of harmonic functions on X.
Received November 18, 1999; in final form January 18, 2000 / Published online April 12, 2001 相似文献
18.
19.
We show that a three-dimensional contact metric manifold is locally homogeneous if and only if it is ball-homogeneous and
satisfies the condition ∇ξτ=2aτϕ, with a constant. Then, we relate the condition ∇ξτ=0 with the existence of taut contact circles on a compact three-dimensional contact metric manifold.
Entrata in Redazione il 20 gennaio 1999.
Supported by funds of the University of Lecce and the M.U.R.S.T. Work made within the program of G.N.S.A.G.A.-C.N.R. 相似文献
20.
We prove that a Jordan system satisfies a polynomial identity if and only if it satisfies a homotope polynomial identity.
In the obtention of that result, we also prove an analogue for associative pairs with involution of Amitsur’s theorem on associative
algebras satisfying a polynomial identity with involution. 相似文献