ACTA issues

Notes on planar semimodular lattices II. Congruences

G. Gr├Ątzer, E. Knapp

Acta Sci. Math. (Szeged) 74:1-2(2008), 37-47
6001/2009

Abstract. We show that in a finite semimodular lattice, the ordering of join-irreducible congruences is done in a special type of sublattice, we call a tight $S_7$.


AMS Subject Classification (1991): 06C10, 06B10

Keyword(s): Semimodular lattice, planar, congruence, prime interval


Received April 21, 2007, and in final form January 31, 2008. (Registered under 6001/2009.)