HenrikRüping's user avatar
HenrikRüping's user avatar
HenrikRüping's user avatar
HenrikRüping
  • Member for 14 years, 1 month
  • Last seen this week
53 votes
4 answers
6k views

Are the rationals homeomorphic to any power of the rationals?

18 votes
3 answers
4k views

Is a inverse limit of compact spaces again compact ?

32 votes
3 answers
4k views

Which spaces are inverse limits of discrete spaces ?

3 votes
1 answer
3k views

Is a proper quotient map closed ?

15 votes
4 answers
3k views

Automorphisms of $SL_n(\mathbb{Z})$

33 votes
1 answer
3k views

Collatz conjecture for numbers of th form $2^n +1$

5 votes
2 answers
2k views

Iterated calculation of determinants

26 votes
7 answers
2k views

Tetrahedra with prescribed face angles

4 votes
2 answers
2k views

Are isometries the only geodesic preserving maps in a CAT(0)-space?

22 votes
5 answers
2k views

When is a extension of $\mathbb{Z}$ by a free group a CAT(0) group?

18 votes
2 answers
1k views

Are there space filling curves for the Hilbert cube?

2 votes
1 answer
1k views

Finding saturated open sets

9 votes
3 answers
1k views

Are subgroups of hyperbolic groups quasiisometrically embedded ?

12 votes
4 answers
1k views

Topologizing free abelian groups

7 votes
3 answers
1k views

Group rings of infinite products of groups

5 votes
2 answers
1k views

Structure theorem of f.g. modules over a (non) PID

8 votes
1 answer
1k views

Is there an elementary way to show the triangular inequality for this expression ?

8 votes
5 answers
1k views

Analogues of the dihedral group

13 votes
4 answers
1k views

Can Lipschitz maps increase the Lebesgue dimension ?

15 votes
2 answers
1k views

infinite dimensional CAT(0) groups

12 votes
2 answers
940 views

Borromean braids

8 votes
1 answer
887 views

geodesic 2-dimensional submanifolds of a Riemannian manifold [duplicate]

11 votes
4 answers
880 views

Are there unique geodesics in the NIL and SOL geometry?

5 votes
3 answers
856 views

Additive functions on a lattice

3 votes
1 answer
797 views

When is the realization of a simplicial space compact ?

11 votes
1 answer
776 views

Are these abelian groups free?

15 votes
0 answers
746 views

Are all these groups CAT(0) groups?

7 votes
1 answer
719 views

Is there an amenabilization of groups ?

17 votes
1 answer
693 views

Outer automorphisms of finite extensions

8 votes
1 answer
672 views

Is every solvable subgroup of $GL(n,\mathbb{Z})$ polycyclic?