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David J. Webb's user avatar
David J. Webb's user avatar
David J. Webb
  • Member for 3 years, 11 months
  • Last seen more than 1 year ago
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Is there a nice characterization of degrees which compute no c.e.a. set?
It is what the kind of thing I want! The paper you mentioned led me to one by Wei Wang with mentioned that first result, so thank you again
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Is there a nice characterization of degrees which compute no c.e.a. set?
Ooh, I hadn’t seen those, thanks!
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Is there a nice characterization of degrees which compute no c.e.a. set?
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Is there a nice characterization of degrees which compute no c.e.a. set?
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 Scholar
accepted
Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
I now suspect the relativization of Martin is not as nice as I hoped, which nixes my comments about an equivalent characterization.
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
Mm, I did delete that since the question was settled, so I suppose it comes down to whether I understand correctly how to relativize Martin's result that every high c.e. degree contains a maximal set - it should be that every A-high, A-c.e. degree contains an A-maximal set, but I haven't worked through the details
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
Ah, okay, Bjorn and I somehow missed that. That settles it!
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Sets $A$ such that $A$-maximal sets are $\Delta^0_2$
When we say it's $A$-high, doesn't that only give that $(B\oplus A)'$ is above $A$, not necessarily $B$ itself?
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