On the grading numbers of direct products of chains |
| |
Authors: | CC Chen KM Koh SC Lee |
| |
Institution: | Dept. of Mathematics, National University of Singapore, Kent Ridge, Singapore 0511 |
| |
Abstract: | For a finite lattice L, denote by and respectively the upper length and lower length of L. The grading number g(L) of L is defined as where Sub(L) is the sublattice-lattice of L. We show that if K is a proper homomorphic image of a distributive lattice L, then ; and derive from this result, formulae for and g(L) where L is a product of chains. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|