English

On the theory of Lucas coloring

Combinatorics 2025-01-14 v4

Abstract

In this paper, we introduce the notion of "LucasColoringLucas-Coloring" associated with a planar graph gg. When gg is a 44-regular, the enumeration of LucasColoringLucas-Coloring has an interesting interpretation. Specifically, it yields a numerical invariant of the associated Khovanov-Lee complex of any link diagram DD whose projection is equal to gg. This complex resides in the Karoubi envelope of Bar-Natan's formal cobordism category, Cob/l3Cob^{3}_{/l} . The Karoubi envelope of Cob/l3Cob^{3}_{/l} was introduced by Bar-Natan and Morrison to provide a conceptual proof of Lee's theorem. As an application of "Lucas-Coloring", we first show how the Alternating Sign Matrices can be retrieved as a special case of LucasColoringLucas-Coloring. Next, we show a certain statistic on the LucasColoringLucas-Coloring enumerates the perfect matchings of a canonically defined graph on gg. This construction allowed us to derive a summation formula of the enumeration of lozenge tilings of the region constructed out of a regular hexagon by removing the "maximal staircase" from its alternating corners in terms of powers of 22. This formula is reminiscent of the celebrated Aztec Diamond Theorem of Elkies, Kuperberg, Larsen, and Propp, which concerns domino tilings of Aztec Diamonds.

Keywords

Cite

@article{arxiv.2410.12751,
  title  = {On the theory of Lucas coloring},
  author = {Pravakar Paul},
  journal= {arXiv preprint arXiv:2410.12751},
  year   = {2025}
}