David Feldman's user avatar
David Feldman's user avatar
David Feldman's user avatar
David Feldman
  • Member for 13 years, 4 months
  • Last seen this week
382 votes
115 answers
105k views

Not especially famous, long-open problems which anyone can understand

97 votes
19 answers
36k views

Collecting proofs that finite multiplicative subgroups of fields are cyclic

85 votes
17 answers
6k views

Important open problems that have already been reduced to a finite but infeasible amount of computation

66 votes
1 answer
4k views

(Approximately) bijective proof of $\zeta(2)=\pi^2/6$?

52 votes
8 answers
5k views

What are the external triumphs of matroid theory?

50 votes
2 answers
6k views

Does Godel's incompleteness theorem admit a converse?

49 votes
4 answers
6k views

If the Riemann Hypothesis fails, must it fail infinitely often?

44 votes
8 answers
6k views

What makes a theorem *a* "nullstellensatz."

39 votes
1 answer
1k views

Modeling question: how often does "the world's oldest person" die?

36 votes
3 answers
5k views

Mazur's unpublished manuscript on primes and knots?

35 votes
3 answers
10k views

The deep significance of the question of the Mandelbrot set's local connectedness?

27 votes
2 answers
877 views

Careless packing

27 votes
1 answer
2k views

A puzzling remark of Manin (ICM 1978)

26 votes
1 answer
2k views

Nontrivial circular arguments?

24 votes
12 answers
3k views

Constructions unique up to non-unique isomorphism

24 votes
1 answer
610 views

Permutations, stopping times, Bessel functions, hook formula and Robinson-Schensted

23 votes
1 answer
1k views

Concerning the rarity of provably transcendental real numbers

23 votes
1 answer
737 views

The Euler-Mascheroni constant and entropy

20 votes
1 answer
1k views

The square root of Wilson's theorem when $p\equiv 1 \mod 4$

20 votes
1 answer
872 views

Does the Fourier expansion of the j-function have any prime coefficients?

20 votes
2 answers
2k views

Tennenbaum's Theorem and polynomials

20 votes
3 answers
2k views

A particular combinatorial proof of Wilson's theorem

20 votes
1 answer
2k views

What are the generalizations of the 27 lines on a cubic surface?

20 votes
10 answers
6k views

Not especially famous, long-open problems which higher mathematics beginners can understand

18 votes
3 answers
1k views

Games that never begin

18 votes
3 answers
985 views

An equivalence relation on group actions

18 votes
3 answers
2k views

Research level applications of "row rank = column rank"?

17 votes
2 answers
934 views

Where and when did "transition to abstraction" courses start?

16 votes
1 answer
878 views

Hearing the 17 planar symmetry groups

16 votes
1 answer
646 views

Galois theory: Generalization of Abel’s Theorem? (Better version!)

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