When is the complement of the diagonal of a LOTS functionally countable?

Luis Enrique Gutiérrez-Domínguez, Rodrigo Hernández-Gutiérrez

In a 2021 paper, Vladimir Tkachuk asked whether there is a non-separable LOTS $X$ such that $X^2\setminus \{⟨x,x⟩:x\in X\}$ is functionally countable. In this pap…