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Danu
  • Member for 10 years, 7 months
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10 votes
2 answers
645 views

Why should the generalization of a 'sequence' be called a 'net'?

9 votes
1 answer
283 views

How does one show that $SO(6)/U(3)\cong \Bbb C\rm P^3$?

8 votes
4 answers
813 views

Cauchy sequences - can we control the rate at which elements "get closer"?

5 votes
1 answer
346 views

Is there a slick proof for the identity that expresses the inner product of imaginary octonions in terms of the cross product?

4 votes
1 answer
244 views

Does a presheaf whose étalé space is Hausdorff always satisfy the identity theorem?

4 votes
1 answer
3k views

How does one prove that a space is dense in another under some norm?

3 votes
2 answers
116 views

How do I express this vector field, given "in terms of $\mathbb{C}$", in the standard notation for derivations?

2 votes
2 answers
113 views

A technical detail in the construction of a covering space: Is the projection $p$ continuous without assuming semilocal simple connectedness?

2 votes
1 answer
956 views

The first 'easy exercise' in Spivak's differential geometry book

1 vote
1 answer
784 views

How to deal with discontinuous points when proving that step functions are dense in $PC[a,b]$

1 vote
1 answer
313 views

What does it mean to ''construct a Riemann-Stieltjes integral''?

1 vote
0 answers
313 views

Applying the duality between infimum and supremum

1 vote
0 answers
182 views

Are there any general existence results for Leray coverings?

1 vote
1 answer
65 views

How do I evaluate this sum, which expresses the Euler characteristic of a degree $d$ hypersurface in $\Bbb C\mathrm P^{n+1}$?