2024/06/20 by Christoph Minz, Minz, Christoph
Business, Management and Accounting · #06A06 #06A07 #06A11 #18B35 #52B15 #83C27 #Combinatorics (math.CO) #FOS: Mathematics #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Mathematical Physics (math-ph) #Optics and Image Analysis
paper · pdf · doi:10.48550/arxiv.2406.14533
openalex publication_date 2024/06/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Partially ordered sets (posets) play a universal role as an abstract structure in many areas of mathematics. For finite posets, an explicit enumeration of distinct partial orders on a set of unlabelled elements is known only up to a cardinality of 16 (listed as sequence A000112 in the OEIS), but closed expressions are unknown. By considering the automorphisms of (finite) posets, I introduce a formulation of local symmetries. These symmetries give rise to a division operation on the set of posets and lead to the construction of symmetry classes that are easier to characterise and enumerate. Furthermore, we consider polynomial expressions that count certain subsets of posets with a large number of layers (a large height). As an application in physics, local symmetries or rather their absence helps to distinguish causal sets (locally finite posets) that serve as discrete spacetime models from generic causal sets.