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The degrees of categoricity above 0’’
Consider the ordering \(\omega\) of the natural numbers \(0\leq 1\leq 2\leq 3\leq\dots\). We can build an isomorphic order \(\mathcal B\) (for bad) as follow...
Turing degrees that compute HYP but can not compute Kleene’s O.
Let \(HYP\) be the set of hyperarithmetic degrees, i.e. \(HYP=\{ \mathbf d:\exists (\alpha<\omega_1^{\mathrm{CK}}) \mathbf d< \mathbf 0^{(\alpha)}\}.\)...
New preprint on arXiv!
My newest preprint Degree spectra of analytic complete equivalence relations just appeared on arXiv.