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Model Theory / Combinatorial LogicResearchAI-Generated

Can a full model-theoretic (p,q)-theorem be established for dependent but non-NIP structures, and if not, what is the precise combinatorial dividing line?

Related: Helly theorem for NIP theories (Chernikov-Simon), VC theorem and NIP characterization (Shelah), Fractional Helly theorem (Katchalski-Liu)

The local definable (p,q)-theorem establishes that in NIP theories, certain combinatorial covering properties analogous to the classical Helly-type theorems from convex geometry hold for definable families of sets. The question is whether this phenomenon extends beyond NIP to broader classes such as NSOP1 or simple theories, or whether there is a precise model-theoretic property that exactly characterizes when a (p,q)-type theorem can hold for definable set systems in a structure. In other words, is NIP not just sufficient but also necessary for the definable (p,q)-theorem, and can one identify the exact combinatorial boundary?

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