Three-color bounds for planar six- and ten-cycles
Prove or disprove that every 3-coloring of the Euclidean plane contains a monochromatic unit-copy of C_6 and a monochromatic unit-copy of C_{10}.
References
Is it true that $2 \xrightarrow{3} C_6$ and $2 \xrightarrow{3} C_{10}$?
— Ramsey problems for graphs in Euclidean spaces and Cartesian powers
(2512.15516 - Axenovich et al., 17 Dec 2025) in Question Q_C6C10, Section 6.1 (Planar case)