English

S-Glued sums of lattices

Combinatorics 2024-12-12 v3

Abstract

For many equation-theoretical questions about modular lattices, Hall and Dilworth give a useful construction: Let L0L_0 be a lattice with largest element u0u_0, L1L_1 be a lattice disjoint from L0L_0 with smallest element v1v_1, and aL0a \in L_0, bL1b \in L_1 such that the intervals [a,u0][a, u_0] and [v1,b][v_1, b] are isomorphic. Then, after identifying those intervals you obtain L0L1L_0 \cup L_1, a lattice structure whose partial order is the transitive relation generated by the partial orders of L0L_0 and L1L_1. It is modular if L0L_0 and L1L_1 are modular. Since in this construction the index set {0,1}\{0, 1\} is essentially a chain, this work presents a method -- termed S-glued -- whereby a general family Lx (xS)L_x\ (x \in S) of lattices can specify a lattice with the small-scale lattice structure determined by the LxL_x and the large-scale structure determined by SS. A crucial application is representing finite-length modular lattices using projective geometries.

Keywords

Cite

@article{arxiv.2409.10738,
  title  = {S-Glued sums of lattices},
  author = {Christian Herrmann and Dale R. Worley},
  journal= {arXiv preprint arXiv:2409.10738},
  year   = {2024}
}

Comments

19 pages, 8 figures. German original by Christian Herrmann, English translation by Dale R. Worley. Added a footnote 1 to give more detail about Dilworth's work on the subject. Added translator's notes at end