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61.
For a regular semigroup with an inverse transversal, we have Saito’s structureW(I,S
o, Λ, *, {α, β}). We represent congruences on this kind of semigroups by the so-called congruence assemblage which consist
of congruences on the structure component partsI,S
o and Λ. The structure of images of this type of semigroups is also presented.
This work is supported by Natural Science Foundation of Guangdong Province 相似文献
62.
Pooya Hatami 《Journal of Combinatorial Theory, Series A》2008,115(7):1103-1113
It is proved that every n×n Latin square has a partial transversal of length at least n−O(log2n). The previous papers proving these results (including one by the second author) not only contained an error, but were sloppily written and quite difficult to understand. We have corrected the error and improved the clarity. 相似文献
63.
Summary It is proved that if the nonempty intersection of bounded closed convex sets A nB is contained in (A + F )U(B +F ) and one of the following holds true: (i) the space X is less-than-three dimensional, (ii) A UB is convex, (iii) F is a one-point set, then A nB CA +F or A nB CB +F (Theorems 2 and 3). Moreover, under some hypotheses the characterization of A and B such that A nB is a summand of A UB is given (Theorem 3). 相似文献
64.
Izu Vaisman 《Annals of Global Analysis and Geometry》2001,19(3):209-234
The transversal twistor space of a foliation
of an even codimension is the bundle
of the complex structures of the fibers of the transversalbundle of
. On
there exists a foliation
by covering spaces of the leaves of
, and any Bottconnection of
produces an ordered pair
of transversal almost complex structures of
. The existence of a Bott connection which yields a structure
1 that is projectable to the space of leaves isequivalent to the fact that
is a transversallyprojective foliation. A Bott connection which yields a projectablestructure
2 exists iff
isa transversally projective foliation which satisfies a supplementarycohomological condition, and, in this case,
1is projectable as well.
2 is never integrable.The essential integrability condition of
1 isthe flatness of the transversal projective structure of
. 相似文献
65.
66.
67.
MAO Feng SHI YiPeng XUAN LiJun SU WeiDong & WU JieZhi State Key Laboratory for Turbulence Complex Systems College of Engineering Peking University Beijing China University of Tennessee Space Institute Tullahoma TN USA 《中国科学:物理学 力学 天文学(英文版)》2011,(6)
As a continuation of a recent linear analysis by Mao et al.(Acta Mech Sin,2010,26:355),in this paper we propose a general theoretical formulation for the compressing process in complex Newtonian fluid flows,which covers gas dynamics,aeroacoustics,nonlinear thermoviscous acoustics,viscous shock layer,etc.,as its special branches.The principle on which our formulation is based is the maximally natural and dynamic Helmholtz decomposition of the Navier-Stokes equation,along with the kinematic Helmholtz decompos... 相似文献
68.
C. Grotta Ragazzo 《Journal of Dynamics and Differential Equations》1994,6(1):227-244
We consider the parametrized family of equations
tt
,u-
xx
u-au+u
2
2
u=O,x(0,L), with Dirichlet boundary conditions. This equation has finite-dimensional invariant manifolds of solutions. Studying the reduced equation to a four-dimensional manifold, we prove the existence of transversal homoclinic orbits to periodic solutions and of invariant sets with chaotic dynamics, provided that =2, 3, 4,.... For =1 we prove the existence of infinitely many first integrals pairwise in involution. 相似文献
69.
Embracing a multisemiotic approach, this case study addresses the ways in which prospective middle school mathematics teachers use linguistic signifiers idiosyncratic to the Turkish language to construe mathematical meaning of angles formed by two lines cut by a transversal. Also, students’ mathematical referents to explain angle relationships were characterized. Six students (3 female, 3 male) volunteered to participate in an individual task-based interview. The results indicated that students used morphological units of meaning when they explained the mathematical concepts. Also, most students used the parallelism of the two lines cut by a transversal as a qualifier to be able to talk about the angle pairs on a transversal. They most often recited properties, such as the U property, to explain the angle relationships. Implications for future research are provided. 相似文献
70.
本文引入并研究了左简纯正断面, 得到了与之相关的若干刻画; 推广并丰富了Blyth 和AlmeidaSantos 于1996 年得到的关于左简逆断面及Kong 于2007 年得到的关于纯正断面的相关结果; 同时,给出了具有左简纯正断面的正则半群的结构定理. 相似文献