Question

$P_1 \vee P_2 $ , $Q_1 \vee Q_2 $ are semi-decidable predicates and $P_2 = \overline{Q_2}$. What can be said about $P_1 \vee Q_1 $?

score 123 · Answer 1 · 2015-10-30 09:22:27

$P_1 \vee P_2 $ , $Q_1 \vee Q_2 $ are semi-decidable predicates and $P_2 = \overline{Q_2}$. What can be said about $P_1 \vee Q_1 $?

score 218 · Answer 2 · 2015-10-31 21:06:46

218

Views

Does there exist a valid first-order formula whose Skolemization is satisfiable only with uncomputable functions?

Published on 31 Oct 2015 - 21:06

score 75 · Answer 3 · 2015-11-01 20:34:32

75

Views

$f,g_1,...,g_k$ computable imply $h(x_1,...,x_n)=f(g_1(x_1,...,x_n),...,g_k(x_1,..,x_n))$ computable. Does the converse hold?

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score 217 · Answer 4 · 2015-11-01 21:54:27

217

Views

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score 52 · Answer 5 · 2015-11-01 21:55:56

52

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score 37 · Answer 6 · 2026-03-25 11:54:22

37

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score 80 · Answer 15 · 2026-03-31 16:14:48

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List Question

$P_1 \vee P_2 $ , $Q_1 \vee Q_2 $ are semi-decidable predicates and $P_2 = \overline{Q_2}$. What can be said about $P_1 \vee Q_1 $?

Does there exist a valid first-order formula whose Skolemization is satisfiable only with uncomputable functions?

$f,g_1,...,g_k$ computable imply $h(x_1,...,x_n)=f(g_1(x_1,...,x_n),...,g_k(x_1,..,x_n))$ computable. Does the converse hold?

Why would proving:$f \in PRC \rightarrow g(y,x_1,...,x_n)=\sum_{t=0}^yf(t,x_1,..,x_n)\in PRC$ by induction be wrong?

Can we make witnesses for membership of $\Sigma_2$ sets unique?

Proving correctness for code computing function.

Language decidability and Post's theorem

How can I write a partial recursive function "maximum(x,y,z)"?

What lies between primitive recursion and total recursion?

Book on Curry-Howard Isomorphisms

Understanding AI through a complexity function

Abstract machines that compute primitive recursive functions

The approximability of different NP-hard problems

Show that the problem of deciding whether a Turing machine prints something is undecidable

Positive existential theory of an extension of the ring

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