English

Directed Hamiltonicity in Generalized Kneser Graphs

Combinatorics 2026-05-28 v2 Commutative Algebra

Abstract

We prove that the canonical orientation of the generalized Kneser graph KG(n,k,s)KG(n,k,s) contains a directed Hamiltonian cycle for all integers s3s \geq 3 and n>skn>sk. Furthermore, we establish that the dichromatic number of this oriented graph is exactly kk. As a special case, our results apply to the ss-stable Kneser graphs Ks-stab(n,k)K_{s\text{-stab}}(n,k), resolving their directed Hamiltonicity and dichromatic number. Our proof adapts the class graph framework of Ledezma and Pastine to the directed setting, leveraging cyclic rotations and friend class adjacencies to construct a single directed cycle spanning all vertices. This work provides a unified and strengthened perspective on the Hamiltonian properties of Kneser-type graphs.

Cite

@article{arxiv.2511.12553,
  title  = {Directed Hamiltonicity in Generalized Kneser Graphs},
  author = {Shahram Mehry},
  journal= {arXiv preprint arXiv:2511.12553},
  year   = {2026}
}

Comments

The current version no longer reflects the intended scope and mathematical rigor of the work

R2 v1 2026-07-01T07:39:41.339Z