On principal congruences and the number of congruences of a lattice with more ideals than filters

被引:2
作者
Czedli, Gabor [1 ]
Muresan, Claudia [2 ]
机构
[1] Univ Szeged, Bolyai Inst, H-6720 Szeged, Hungary
[2] Univ Bucharest, Fac Math & Comp Sci, RO-010014 Bucharest, Romania
来源
ACTA SCIENTIARUM MATHEMATICARUM | 2019年 / 85卷 / 3-5期
关键词
lattice ideal; lattice filter; simple lattice; more ideals than filters; number of ideals; cardinality; lattice congruence; principal congruence; HOMOMORPHISMS;
D O I
10.14232/actasm-018-538-y
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
Let lambda and kappa be cardinal numbers such that kappa is infinite and either 2 <= lambda <= kappa, or lambda = 2(kappa). We prove that there exists a lattice L with exactly lambda many congruences, 2(kappa) many ideals, but only kappa many filters. Furthermore, if lambda >= 2 is an integer of the form 2(m) center dot 3(n), then we can choose L to be a modular lattice generating one of the minimal modular nondistributive congruence varieties described by Ralph Freese in 1976, and this L is even relatively complemented for lambda = 2. Related to some earlier results of George Gratzer and the first author, we also prove that if P is a bounded ordered set (in other words, a bounded poset) with at least two elements, G is a group, and kappa is an infinite cardinal such that kappa >= vertical bar P vertical bar and kappa >= vertical bar G vertical bar, then there exists a lattice L of cardinality kappa such that (i) the principal congruences of L form an ordered set isomorphic to P, (ii) the automorphism group of L is isomorphic to G, (iii) L has 2(kappa) many ideals, but (iv) L has only kappa many filters.
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页码:363 / 380
页数:18
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