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Distinguishing regular graphs from lists

Jakub Kwaśny, Marcin Stawiski

TL;DR

This work addresses distinguishing edge colourings from lists in connected regular graphs, proving that for graphs of order at least $7$ (finite or countable) there exists a distinguishing edge colouring from lists of length $2$, i.e. $D'_l(G) ≤ 2$, with an analogous extension for $\kappa$-regular graphs where $\kappa$ is a fixed point of the aleph hierarchy. It develops a constructive approach: a rooted-automorphism framework with a phase-based colouring for locally finite graphs, and a vertex-palette encoding method for graphs of infinite degree, to guarantee a two-colour distinguishing colouring from lists. The paper also establishes $D'_l(K_n)=2$ for $n≥6$ via asymmetric spanning subgraphs and discusses forcing-based consistency results for $2^{\kappa}$-regular graphs, broadening the applicability to both finite and infinite regular graphs. These results advance the understanding of list-distinguishing indices, connect to the Infinite Motion Conjecture, and provide a versatile framework for automorphism-breaking in regular graphs across cardinalities.

Abstract

An edge colouring of a graph is called distinguishing if there is no non-trivial automorphism which preserves it. We prove that every at most countable, finite or infinite, connected regular graph of order at least $7$ admits a distinguishing edge colouring from any set of lists of length $2$. Furthermore, we show that the same holds for connected regular graphs of order $κ$ where $κ$ is a fixed point of the aleph hierarchy.

Distinguishing regular graphs from lists

TL;DR

This work addresses distinguishing edge colourings from lists in connected regular graphs, proving that for graphs of order at least (finite or countable) there exists a distinguishing edge colouring from lists of length , i.e. , with an analogous extension for -regular graphs where is a fixed point of the aleph hierarchy. It develops a constructive approach: a rooted-automorphism framework with a phase-based colouring for locally finite graphs, and a vertex-palette encoding method for graphs of infinite degree, to guarantee a two-colour distinguishing colouring from lists. The paper also establishes for via asymmetric spanning subgraphs and discusses forcing-based consistency results for -regular graphs, broadening the applicability to both finite and infinite regular graphs. These results advance the understanding of list-distinguishing indices, connect to the Infinite Motion Conjecture, and provide a versatile framework for automorphism-breaking in regular graphs across cardinalities.

Abstract

An edge colouring of a graph is called distinguishing if there is no non-trivial automorphism which preserves it. We prove that every at most countable, finite or infinite, connected regular graph of order at least admits a distinguishing edge colouring from any set of lists of length . Furthermore, we show that the same holds for connected regular graphs of order where is a fixed point of the aleph hierarchy.
Paper Structure (3 sections, 9 theorems)

This paper contains 3 sections, 9 theorems.

Key Result

Theorem 1

Let $G$ be a connected graph that is neither a double ray, a symmetric nor a bisymmetric tree, $K_2$, $K_3$, $K_4$, $K_5$, $K_{3,3}$, $C_n$. Then $D'_l(G) \le \Delta(G)-1$.

Theorems & Definitions (21)

  • Theorem 1: Kwaśny, Stawiski KS_list_general
  • Conjecture 2
  • Theorem 3
  • Theorem 4
  • Theorem 5
  • Conjecture 6
  • Conjecture 7: Broere, Pilśniak 2015 BP
  • Conjecture 8
  • Lemma 9
  • proof
  • ...and 11 more