TY - JOUR ID - Grzelec2025 LB - Grzelec2025 AU - Grzelec, Igor AU - Madaras, Tomáš AU - Onderko, Alfréd TI - On uniqueness of packing of three copies of 2-factors ST - On uniqueness of packing of three copies of 2-factors JO - Opuscula Math. JA - Opuscula Math. JF - Opuscula Mathematica PY - 2025 VL - 45 IS - 1 SP - 79 EP - 101 DO - https://doi.org/10.7494/OpMath.2025.45.1.79 UR - https://doi.org/10.7494/OpMath.2025.45.1.79 AB - The packing of three copies of a graph \(G\) is the union of three edge-disjoint copies (with the same vertex set) of \(G\). In this paper, we completely solve the problem of the uniqueness of packing of three copies of 2-regular graphs. In particular, we show that \(C_3,C_4,C_5,C_6\) and \(2C_3\) have no packing of three copies, \(C_7,C_8,C_3 \cup C_4, C_4 \cup C_4, C_3 \cup C_5\) and \(3C_3\) have unique packing, and any other collection of cycles has at least two distinct packings. KW - uniquely packable graph KW - 2-factor KW - 3-packing SN - 1232-9274 ER -