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Georg Lehner's user avatar
Georg Lehner's user avatar
Georg Lehner's user avatar
Georg Lehner
  • Member for 10 years, 8 months
  • Last seen this week
31 votes
2 answers
5k views

The philosophy behind local rings

26 votes
1 answer
917 views

The analogy between dualizable categories and compact Hausdorff spaces

25 votes
1 answer
1k views

Examples of $(\infty,1)$-topoi that are not given as sheaves on a Grothendieck topology

25 votes
1 answer
2k views

A geometric theory of Blueprints? (Algebras over the field with one element)

20 votes
3 answers
3k views

Alternate proofs of Hilberts Basis Theorem

14 votes
3 answers
2k views

Is there a universal property characterizing the category of compact Hausdorff spaces?

14 votes
1 answer
1k views

Relating two different approaches to the Atiyah-Hirzebruch Spectral Sequence

13 votes
2 answers
830 views

Proving Kashiwara–Schapira's micro-local cutoff lemma $\infty$-categorically

11 votes
1 answer
2k views

The set of subgroups of $F_2$

10 votes
1 answer
477 views

Definition of $Fun^G( \mathcal C, \mathcal D)$ in the setting of quasicategories

10 votes
0 answers
439 views

"Generalized theory of polynomials" for a given commutative Lawvere Theory

10 votes
1 answer
415 views

In what sense is the double negation topology functorial?

8 votes
2 answers
609 views

A lattice/topos-theoretic construction of the Boolean algebra of measurable subsets modulo nullsets

8 votes
1 answer
281 views

Finite group such that $K_{-1} (\mathbb Z G)$ has non-trivial torsion

8 votes
0 answers
148 views

The homotopy inverse on Quillen's $S^{-1}S$ construction

7 votes
1 answer
436 views

Commuting homotopy colimits and arbitrary products in spaces

7 votes
1 answer
270 views

Idempotent $H$-structures / Higher join-semilattices are discrete?

7 votes
1 answer
317 views

When is the category of sheaves on a site compactly assembled/a continuous category?

5 votes
0 answers
192 views

Resources on a smooth topos containing complex analytic/holomorphic geometry

5 votes
0 answers
252 views

Realizing the 0-th Postnikov truncation of a spectrum in the category of orthogonal/symmetric spectra

4 votes
1 answer
587 views

The "$\infty$"-column in the periodic table of n-categories

4 votes
0 answers
122 views

How to describe a concrete generator of $\widetilde{K_0(\mathbb{Z}[C_{23}])} \cong \widetilde{K_0(\mathbb{Z}[\zeta_{23}])}$

4 votes
1 answer
214 views

Injectivity of assembly in A-theory for $BC_2 = \mathbb R P^\infty$ in degree $4$

3 votes
0 answers
134 views

Constructive formula for Haar measure of a compact subset