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justin
  • Member for 8 years, 8 months
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58 votes
10 answers
6k views

Is it an abuse of language to say "*the* integers," "*the* rational numbers," or "*the* real numbers," etc.?

38 votes
7 answers
4k views

Do the axioms of set theory actually define the notion of a set?

31 votes
9 answers
4k views

Is formal truth in mathematical logic a generalization of everyday, intuitive truth?

17 votes
3 answers
2k views

Should this "definition" of set equality be an axiom?

12 votes
2 answers
1k views

How to prove that Gödel's Incompleteness Theorems apply to ZFC?

11 votes
3 answers
1k views

Is the "domain of discourse" in axiomatic set theory also a "set"?

11 votes
2 answers
2k views

Is it circular to define the Von Neumann universe using "sets"?

11 votes
1 answer
2k views

Are categories larger than classes?

9 votes
2 answers
2k views

Terry Tao's computational perspective on set theory

8 votes
0 answers
275 views

What system was Grothendieck working in when he introduced universes?

7 votes
0 answers
124 views

Does introducing a new type create a different extension, and is it still conservative?

7 votes
1 answer
185 views

Do mathematical objects have underlying types?

6 votes
3 answers
367 views

Confusion in proof that primes $p = 4k + 1$ are uniquely the sums of two squares

6 votes
3 answers
3k views

Eigenvalues of a Permutation?

5 votes
1 answer
1k views

Left-invariant vector fields on the circle $S^1$

4 votes
2 answers
426 views

The difference between a finite set and an ordered $n-$tuple? Proving the set of all finite subsets of a countable set is countable.

4 votes
4 answers
874 views

Do these theorems about power sets hold for the empty set?

4 votes
3 answers
3k views

Proving that cardinality of the reals = cardinality of $[0,1]$

4 votes
1 answer
787 views

Is every isomorphism of an algebraically closed field onto one of its subfields an automorphism?

4 votes
1 answer
505 views

Smooth function on a manifold not dependent on coordinate chart

4 votes
1 answer
223 views

Proving that extension by radicals implies solvable group

4 votes
2 answers
326 views

If $\overline A\cap B = A\cap \overline B = \varnothing$, $A\cup B$ is disconnected.

4 votes
1 answer
673 views

In $\mathbb Q_p$, proving every open ball is the disjoint union of more than one open ball

4 votes
2 answers
1k views

Proving that the cross ratio is a Möbius transformation

4 votes
1 answer
315 views

Why do we write $df/dx$ instead of $df/dx(x)$?

3 votes
1 answer
1k views

Pronouncing the symbols $\oplus,\otimes,\rtimes,\cup$, and $\cap$. [closed]

3 votes
2 answers
2k views

Smooth functions between manifolds and subsets of manifolds

3 votes
2 answers
11k views

Find all irreducible monic polynomials of degree 3 in $\mathbb Z/3\mathbb Z[x].$

3 votes
1 answer
81 views

Prove there is a basis of $V$ w.r.t. which $T$ is the companion matrix of $a(x)$

3 votes
1 answer
78 views

If $F\cong R^n$, why is $1\otimes \psi\colon F\otimes_R L\to F\otimes_R M$ injective?