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leftaroundabout's user avatar
leftaroundabout's user avatar
leftaroundabout
  • Member for 12 years, 4 months
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79 votes
7 answers
10k views

Is linear algebra more “fully understood” than other maths disciplines?

39 votes
3 answers
10k views

Is it true that a space-filling curve cannot be injective everywhere?

12 votes
2 answers
432 views

Is it mathematically problematic to consider the complex space of real(!)-valued functions?

9 votes
2 answers
280 views

How should one interpret an interval like $[2,1]$?

9 votes
1 answer
367 views

What is the name for the archetypical example of a test function, $\varphi(x)=e^{1/(x^2-1)}$?

8 votes
1 answer
152 views

Is there a permutation on $\mathbb{N}$ that, if repeated often enough, eventually shuffles the whole set?

7 votes
3 answers
1k views

How is the uniform boundedness principle compatible with this seemingly weak convergent sequence?

6 votes
3 answers
2k views

Is self-adjointness really a property of an operator, or of an operator and an inner product?

6 votes
0 answers
84 views

Is there a way to define the concept of manifolds so it looks more like “generalised affine spaces”?

3 votes
1 answer
192 views

Why not define the Conway base-5 function, instead of base-13?

2 votes
1 answer
114 views

Are functions between sets of global elements of objects isomorphic to the hom-set between these objects?

2 votes
1 answer
81 views

Would it be appropriate to use "power" to describe an $n$-fold fold of a number with some associative binary operation? Is there a better expression?

2 votes
1 answer
98 views

What do you call a directed graph in which reachablility is a symmetric relation?

2 votes
2 answers
1k views

Why is the hyperbolic plane homeomorphic to $\mathbb{R}^2$, whilst the 2-sphere isn't?

2 votes
3 answers
89 views

Is there any shorter term for manifolds with boundary?

1 vote
1 answer
145 views

Can you say that almost all $\mathcal{C}^\infty$ functions are not polynomials?

0 votes
2 answers
3k views

How does the left singular value decomposition change when one duplicates a column in the original matrix?