Adler's conjecture on spectra of two-cardinal counting functions

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Let TT be a countable theory and let fT(κ,λ)f_T(\kappa,\lambda) be the associated two-cardinal counting function for infinite cardinals kappaleqlambdakappaleqlambda. Adler's counting-spectrum conjecture. There are only finitely many possible functions fT(κ,λ)f_T(\kappa,\lambda) as TT ranges over countable theories, and the property that TT is NTP2_2 can be detected from fT(κ,λ)f_T(\kappa,\lambda). If TT has TP2_2, the function is maximal, namely fT(κ,λ)=λκf_T(\kappa,\lambda)=\lambda^{\kappa} for all aleph0leqkappaleqlambdaaleph_0leqkappaleqlambda. The first assertion is addressed by later results in the paper, while the second is explicitly refuted by the counterexample identified below.

References

Primary source

Artem Chernikov and Chuyin Jiang, “Fractional Helly property and combinatorics of forking in NTP_2 theories”, arXiv:2605.18123 (2026).

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