MathOverflow

Enlightened

 Enlightened
First to answer and accepted with score of 10 or more. This badge can be awarded multiple times.

earned this badge 76 times.
Is there a theory between HA and PA that doesn't have Markov's rule?
Awarded Feb 7 at 17:42
Does completeness of the theory of a bijection without finite orbits depend on choice?
Awarded Jan 23 at 19:40
What is the minimal density of a set A such that A+A = N?
Awarded Dec 4, 2023 at 20:36
Can a field have an irreducible polynomial of any degree?
Awarded Oct 14, 2023 at 8:25
Is the usual enumeration of $\mathsf{PA}$ "minimal for consistency strength"?
Awarded Jun 15, 2023 at 17:51
Parity of number of solutions to Diophantine equations
Awarded Feb 11, 2023 at 8:32
Systems intermediate in strengthen between Robinson arithmetic and PA
Awarded Dec 12, 2022 at 23:26
Every abelian torsion-free group is strictly totally orderable (via the compactness theorem)
Awarded Nov 7, 2022 at 14:40
Generalizing a result of Kreisel on $\omega$-consistency
Awarded Aug 11, 2022 at 14:02
Reverse Mathematics strength of fixed radius covering theorem
Awarded Mar 31, 2022 at 14:31
How hard is it to say "not exactly $p$" with a Horn sentence?
Awarded Mar 11, 2022 at 14:42
Are these theories of real and complex number biinterpretable?
Awarded Sep 23, 2021 at 12:01
Quantifier elimination for abelian groups
Awarded Aug 30, 2021 at 11:04
Can one show that the real field is not interpretable in the complex field without the axiom of choice?
Awarded Jul 16, 2021 at 13:52
Non-uniform complexity of the halting problem
Awarded Jun 28, 2021 at 14:33
Alternatives to the law of the excluded middle
Awarded May 4, 2021 at 10:48
What is the consistency strength of this theory?
Awarded Apr 15, 2021 at 6:53
Is Tarskian hyperbolic geometry consistent, complete & decidable?
Awarded Apr 8, 2021 at 14:20
What is the theory of the random poset?
Awarded Apr 7, 2021 at 14:36
Large dominating sets in tournaments
Awarded Feb 8, 2021 at 5:43
Decidability of a first-order theory of hyperreals
Awarded Oct 13, 2020 at 16:46
Interpretations of modal logic where $\Box$ means "valid"
Awarded Aug 8, 2020 at 9:42
The inconsistency of Graham Arithmetics plus $ \forall n, n < g_{64}$
Awarded Jul 23, 2020 at 19:40
Can nonstandard fields contain $\mathbb R$ in different ways?
Awarded Apr 11, 2020 at 12:10
What system suffices to show the strength of PRA is $\omega^\omega$?
Awarded Mar 24, 2020 at 23:30
Which lattices are quotients of finite powerset lattices?
Awarded Feb 24, 2020 at 0:30
Does "every" first-order theory have a finitely axiomatizable conservative extension?
Awarded Dec 2, 2019 at 12:30
Convergence rate of Fagin's 0-1 law for first-order properties of random graphs
Awarded Nov 18, 2019 at 22:00
Fibers of the morphism from the free Heyting algebra to the free Boolean algebra
Awarded Mar 15, 2019 at 22:05
Kleene realizability in Peano arithmetic
Awarded Mar 12, 2019 at 21:25
Are all real-closed subfields of $\overline{\mathbb{Q}}$ conjugate?
Awarded Sep 5, 2018 at 3:05
Is this conjecture strictly weaker than P=NP?
Awarded Aug 7, 2018 at 17:35
Does cut elimination fail here?
Awarded Jun 13, 2018 at 17:47
Analog of Tennenbaum's theorem for EFA
Awarded Mar 19, 2018 at 16:57
Is it possible to completely embed complete Heyting Algebras into upsets of a poset?
Awarded Mar 8, 2018 at 23:57
What is this property exhibited by some logical systems?
Awarded Mar 6, 2018 at 11:10
When we count the same set, must the number always be the same?
Awarded Nov 30, 2017 at 3:27
Weakest choice principle required for Robertson-Seymour Graph Minor Theorem?
Awarded Oct 28, 2017 at 8:45
Is there a first-order theory who does not interpret arithmetic yet still does not have a computable consistent completion?
Awarded Sep 8, 2017 at 23:01
Cut-free proofs in ZFC
Awarded Aug 14, 2017 at 5:07
Is there an $E_1$-definition of primality?
Awarded May 15, 2017 at 15:05
Is Kripke Platek theory finitely axiomatizable?
Awarded Apr 5, 2017 at 2:43
Existence of well-ordering of epsilon_0 in weak theories
Awarded Mar 7, 2017 at 18:53
Source for NBG+Equipollence conservative over ZFC?
Awarded Feb 19, 2017 at 12:54
Analysis of Misere Nim?
Awarded Oct 3, 2016 at 20:56
Smallest collection of bases for prime testing of 64 bit numbers?
Awarded Sep 8, 2016 at 22:50
Essential incompleteness via diophantine formulas?
Awarded Jun 22, 2016 at 1:05
Can we find CH in the analytical hierarchy?
Awarded Sep 18, 2015 at 21:27
Countable group with uncountable number of subgroups $< 2^{\aleph_0}$
Awarded Jun 18, 2015 at 7:31
Is factorial definable using a $\Delta_0$ formula?
Awarded Feb 25, 2015 at 16:23
Can ZFC prove it cannot derive an inconsistency in $n$ steps?
Awarded Jan 27, 2015 at 18:23
Which ordered fields are homeomorphic to their power?
Awarded Dec 14, 2014 at 23:59
Formal systems needed to formalize relative independence results
Awarded Dec 9, 2014 at 9:09
a question about connected open sets in $R^2$
Awarded Nov 27, 2014 at 21:08
Set-theoretic tautologies
Awarded Jul 27, 2014 at 11:07
The (un)decidability of Robinson-Arithmetic-without-Multiplication?
Awarded Jul 26, 2014 at 8:14
Are there "non-constructive" sets in second-order arithmetic?
Awarded Jun 25, 2014 at 20:23
When does $ZFC \vdash\ ' ZFC \vdash \varphi\ '$ imply $ZFC \vdash \varphi$?
Awarded Feb 3, 2014 at 22:20
Fields of characteristic zero via ultraproducts
Awarded Jan 31, 2014 at 1:07
Is there exponentiation in "sufficiently large" models of $I\Delta_{0}$?
Awarded Sep 24, 2013 at 13:59
1
2

Others with this badge