Congruence normality: The characterization of the doubling class of convex sets
Congruence normality: The characterization of the doubling class of convex sets
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同余正态性:凸集加倍类的表征
DOI:
10.1007/bf01221793
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发表时间:
1994
影响因子:
0.6
通讯作者:
A. Day
中科院分区:
文献类型:
--
作者:
A. Day
In [2], the author gave characterizations of the classes of all lower, upper or fully bounded (finite) lattices in terms of the doubling construction: viz, they are all finite lattices attainable by starting with 1 and closing the class under the doubling construction using lower pseudo-, upper pseudo-or (ordinary) intervals, respectively. Recently, in [5], Geyer provided a characterization of the" doubling class" of all convex sets. Geyer's characterization and proof however are written in the language of concept lattices, and therefore the roles of traditional lattice concepts, eg join-and meet-irreducibles, congruence relations, etc., are highly non-visible. In this paper we present another characterization of this class, which we call congruence normal, and provide traditional proofs of Geyer's results. We will also attempt to justify the use of the term, congruence normal, by supplying some" good" properties of this class. In particular, we refine Geyer's results to obtain lower, resp. upper, bounded (finite) lattices as congruence normal lattices satisfying the join-, resp. meet-, semidistributive law (SDv), resp.(SD^).