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171.
Motivated by studying fuzzy congruences in groups, semigroups, and ordered semigroups, and as a continuation of N. Kuroki and Y. Tan's works in regular semigroups in terms of fuzzy subsets, in this article we introduce the notions of a fuzzy good congruence relation, a fuzzy cancellative congruence relation on abundant semigroups, and give some properties, and characterizations of fuzzy good congruences on such semigroups. Furthermore, we characterize fuzzy good congruences of left semiperfect abundant semigroups, and get sufficient and necessary conditions for an abundant semigroup to be left semiperfect. 相似文献
172.
Yunhe Sheng 《代数通讯》2013,41(5):1929-1953
Let Y be an integral projective curve whose singularities are of type Ak, i.e. with only tacnodes and planar (perhaps non-ordinary) cusps. Set g:= pa(Y). Here we study the Brill - Noether theory of spanned line bundles on Y. If the singularities are bad enough, we show the existence of spanned degree d line bundles, L, with h0(Y, L) ≥ r + 1 even if the Brill - Noether number ρ(g, d, r) < 0. We apply this result to prove that genus g curves with certain singularities cannot be hyperplane section of a simple K3 surface S ? P g. 相似文献
173.
Cándido Martín González 《代数通讯》2013,41(5):1903-1912
In this note we study associative dialgebras proving that the most interesting such structures arise precisely when the algebra is not semiprime. In fact the presence of some “perfection” property (simpleness, primitiveness, primeness, or semiprimeness) imply that the dialgebra comes from an associative algebra with both products ? and ? identified. We also describe the class of zero-cubed algebras and apply its study to that of dialgebras. Finally, we describe two-dimensional associative dialgebras. 相似文献
174.
Donald W. Barnes 《代数通讯》2013,41(11):4330-4335
I describe the lattice ?(L) of subalgebras of a one-generator Leibniz algebra L. Using this, I show that, apart from one special case, a lattice isomorphism φ: ?(L) → ?(L′) between Leibniz algebras L, L′ maps the Leibniz kernel Leib(L) of L to Leib(L′). 相似文献
175.
176.
177.
Zeynep Özkurt 《代数通讯》2013,41(8):3534-3544
Let F be the free Leibniz algebra of rank two over a field K of characteristic zero freely generated by x 1 and x 2. In this article we show that an endomorphism of F which preserves the orbit of a nontrivial element of F is an automorphism. Using this result, we determine some test elements of F. 相似文献
178.
179.
运用同余及元素阶的性质,证明了对任意的正整数n,丢番图方程(195n)^x+(2Sn)^y=(197n)^z仅有正整数解(x,y,Z)=(2,2,2). 相似文献
180.
In this paper we investigate the semi-discrete Ablowitz–Kaup–Newell–Segur (sdAKNS) hierarchy, and specifically their Lax pairs and infinitely many conservation laws, as well as the corresponding continuum limits. The infinitely many conserved densities derived from the Ablowitz-Ladik spectral problem are trivial, in the sense that all of them are shown to reduce to the first conserved density of the AKNS hierarchy in the continuum limit. We derive new and nontrivial infinitely many conservation laws for the sdAKNS hierarchy, and also the explicit combinatorial relations between the known conservation laws and our new ones. By performing a uniform continuum limit, the new conservation laws of the sdAKNS system are then matched with their counterparts of the continuous AKNS system. 相似文献