3 problems

Schmitz's conjecture. The following are equivalent: (i) the class of structures in $\mathcal{C}$ labelled with any well-quasi-ordered set $(Y,\leq)$ is itself well-quasi-ordered un…

Let a graph have finite tree-width if its tree-width is finite, and consider the minor relation on graphs. Finite-tree-width well-quasi-ordering conjecture. The graphs of finite tr…

A set system is a family of sets, and its dimension $\dim \mathcal{X}$ is its learning-sequence order type. A linearization of a set system is a suitable set system preserving the…