Stack Exchange

Noah Schweber

https://math.berkeley.edu/~schweber/

A graduate student at UC-Berkeley, interested in mathematical logic - specifically, computability theory and reverse mathematics, set theory, and abstract model theory. I'm also interested in other Nifty Things, in mathematics and elsewhere.

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Top Questions
44 votes

When should I be doing cohomology?

logic set-theory homology-cohomology asked Dec 30 '14 at 19:22
math.stackexchange.com

36 votes

What is the intuition between 1-cocycles (group cohomology)?

intuition examples-counterexamples group-cohomology asked Feb 24 '13 at 2:16
math.stackexchange.com

35 votes

Counterexamples in universal algebra

big-list lattices universal-algebra counterexamples asked Jan 9 '14 at 2:51
mathoverflow.net

33 votes

Positive set theory, antifoundation, and the “co-Russell set”

logic set-theory foundations alternative-set-theories asked Sep 15 '17 at 22:44
math.stackexchange.com

31 votes

Godel on recursion-theoretic hierarchies

lo.logic computability-theory descriptive-set-theory reference-request proof-theory asked Mar 26 '13 at 4:52
mathoverflow.net

31 votes

What are some proofs of Godel's Theorem which are *essentially different* from the original proof?

lo.logic model-theory alternative-proof soft-question asked Aug 4 '11 at 3:35
mathoverflow.net

28 votes

Where do uncountable models collapse to?

lo.logic set-theory model-theory forcing asked Oct 14 '15 at 4:45
mathoverflow.net

26 votes

Supercompact and Reinhardt cardinals without choice

lo.logic large-cardinals set-theory axiom-of-choice asked Apr 23 '12 at 1:53
mathoverflow.net

22 votes

On the global structure of the Gromov-Hausdorff metric space

gn.general-topology mg.metric-geometry asked Jul 26 '15 at 17:42
mathoverflow.net

22 votes

Undetermined Banach-Mazur games in ZF?

set-theory lo.logic gn.general-topology descriptive-set-theory infinite-games asked Jan 31 at 21:26
mathoverflow.net

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Top Answers
150
Why is it important for a matrix to be square?
math.stackexchange.com

113
Where are the axioms?
math.stackexchange.com

96
Why are There No “Triernions” (3-dimensional analogue of complex numbers / quaternions)?
math.stackexchange.com

75
Why write ten as $10$ and not as $00$
math.stackexchange.com

74
What does it mean to suspect that two conjectures are logically equivalent?
mathoverflow.net

73
Is there a bijection between the reals and naturals?
math.stackexchange.com

72
Is mathematics just a bunch of nested empty sets?
math.stackexchange.com

68
What's wrong with this reasoning that $\frac{\infty}{\infty}=0$?
math.stackexchange.com

63
What are some important but still unsolved problems in mathematical logic?
mathoverflow.net

62
Hilbert's hotel: why can't I repeat it infinitely many times?
math.stackexchange.com

61
How can I improve my formal definitions?
mathoverflow.net

60
Avoiding proof by induction
math.stackexchange.com

58
Are there any Turing-undecidable problems whose undecidability is independent of the Halting problem?
math.stackexchange.com

55
Why do people accept the axiom of choice given the well ordering principle?
math.stackexchange.com

51
Does the existence of a mathematical object imply that it is possible to construct the object?
math.stackexchange.com

49
Difference between provability and truth of Goodstein's theorem
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48
Is there a function $f:{\mathbb N}\to{\mathbb N}$ that is neither injective nor surjective?
math.stackexchange.com

46
Why aren't all square roots irrational?
math.stackexchange.com

43
Opposite of Fermat's Last Theorem?
math.stackexchange.com

42
Is there a model of ZFC inside which ZFC does not have a model?
math.stackexchange.com

42
Hilbert's alleged proof of the Continuum Hypothesis in “On the Infinite”
mathoverflow.net

41
Do we cite results in Arxiv which are obviously wrong?
academia.stackexchange.com

41
Is there any uncountably infinite set that does not generate the reals?
math.stackexchange.com

40
Set builder notation: Colon or Vertical Line
math.stackexchange.com

40
Implication in mathematics - How can A imply B when A is False?
math.stackexchange.com

40
Is aleph-$0$ a natural number?
math.stackexchange.com

40
Are the rationals on a unit circle dense?
math.stackexchange.com

40
The error in Petrovski and Landis' proof of the 16th Hilbert problem
mathoverflow.net

39
What are some deep theorems, and why are they considered deep?
mathoverflow.net

39
Are there fewer positive integers than all integers?
math.stackexchange.com

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