Unavoidable subprojections in union-closed set systems of infinite breadth

Yemon Choi, Mahya Ghandehari, Hung Le Pham

We consider union-closed set systems with infinite breadth, focusing on three particular configurations ${\mathcal{T}}_{\max }(E)$, ${\mathcal{T}}_{\min }(E)$ and ${\mathcal T}_{…