August 21
Dan Hathaway, University of Vermont
A relative of ${\rm ZF} + {\rm DC} + \omega_1\text{ is measurable'}$

Let $\Phi$ be the statement that for any function $f: \omega_1 \times \omega_1 \to \omega$, there are functions $g_1, g_2 : \omega_1 \to \omega$ such that for all $(x,y) \in \omega_1 \times \omega_1$, we have $f(x,y) \le \text{max }\{g_1(x), g_2(y)\}$. We will show that $\Phi$ follows from ${\rm ZF} + {\rm DC} + \omega_1\text{ is measurable'}$. On the other hand using core models, we will show that $\Phi + \text{the club filter on }\omega_1\text{ is normal'}$ implies there are inner models with many measurable cardinals. We conjecture that $\Phi$ and ${\rm ZF} + {\rm DC} + \omega_1\text{ is measurable'}$ have the same consistency strength. The research is joint with Francois Dorais at the University of Vermont.

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