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ignoramus
  • Member for 8 years, 2 months
  • Last seen more than 1 year ago
  • Orlando, FL, USA
260 votes
17 answers
104k views

Any open subset of $\Bbb R$ is a countable union of disjoint open intervals

43 votes
5 answers
22k views

Intuitive proof of multivariable changing of variables formula (Jacobian) without using mapping and/or measure theory?

  • 7,978
38 votes
6 answers
16k views

Locally Constant Functions on Connected Spaces are Constant

36 votes
5 answers
19k views

Difference between $\mathbb C$ and $\mathbb R^2$ [duplicate]

  • 1,880
17 votes
3 answers
3k views

Complex differentiability vs differentiability in $\mathbb{R}^2$

  • 3,454
17 votes
4 answers
10k views

Number of homomorphisms between two cyclic groups.

  • 2,226
13 votes
2 answers
4k views

$\sin(n)$ subsequence limits set

10 votes
1 answer
452 views

What are the three non-isomorphic 2-dimensional algebras over $\mathbb{R}$?

  • 737
7 votes
3 answers
791 views

Sums of Fourth Powers

  • 163
7 votes
7 answers
1k views

Remark 4.31 in Baby Rudin: How to verify these points?

7 votes
3 answers
4k views

Easiest example of rearrangement of infinite leading to different sums

6 votes
5 answers
384 views

Integrating $ \int_0^\infty \frac{x^5}{e^x+1} \, dx $

  • 71
6 votes
3 answers
2k views

Differential equation involving cross product.

  • 311
5 votes
4 answers
411 views

Series of binomial coefficients: $\sum\limits_{n=k}^{\infty}{\binom nk}x^n=\frac{x^k}{(1-x)^{k+1}}$

5 votes
2 answers
4k views

The zeroth homology group corresponds to path components

4 votes
2 answers
786 views

Help with Baby Rudin Theorem 3.29

  • 1,110
4 votes
3 answers
2k views

absolute convergence implies unconditional convergence

4 votes
1 answer
359 views

Identify all three edges of a single 2-simplex does not produce a Delta-complex structure

  • 439
3 votes
2 answers
1k views

Is $\neg Con(PA)$ true in a model of $PA+\neg Con(PA)$?

3 votes
1 answer
65 views

A question related to convex and compact set

3 votes
2 answers
849 views

Entire function real and imaginary part product

  • 1,167
3 votes
2 answers
102 views

rewrite $\sum_{n=0}^\infty \frac{(-1)^nx^{n-1}}{2^{n+1}}$ as $-\sum_{n=0}^\infty (x+1)^{2n}$

2 votes
1 answer
693 views

Con(PA) implies consistency of $\mathsf{PA}$ + ¬Con($\mathsf{PA}$)

  • 1,471
2 votes
3 answers
747 views

If $P(\Re(f(z)),\Im(f(z)))=0$ where $f$ is holomorphic, than $f$ is constant.

2 votes
1 answer
267 views

Intuition for visualising dense monotonic discontinuous function

  • 435
2 votes
2 answers
246 views

If $f$ has only removable discontinuities, show that $f$ can be adjusted to a continuous function

  • 26.5k
1 vote
1 answer
1k views

Why is the completion of the rationals isometrically isomorphic to the reals constructed by Dedekind cuts? [duplicate]

1 vote
0 answers
166 views

The inverse function theorem, problem with the proof

  • 1,450
1 vote
1 answer
279 views

Linear independence of powers

  • 1,205
0 votes
2 answers
399 views

Find the sum of the series (rearranged harmonic series)

  • 165