User Ingo Blechschmidt

41 votes

Accepted

Joyal's construction of the spectrum of a commutative ring

answered Nov 17, 2015 at 10:17

18 votes

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Is the theory of vector bundles just linear algebra done in a suitable topos?

answered May 4, 2017 at 12:12

16 votes

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Locales as spaces of ideal/imaginary points

answered Jul 21, 2018 at 14:30

13 votes

Do pretopoi have cohomology and homotopy groups?

answered Jan 24, 2022 at 16:03

12 votes

Examples of statements that are valid in every spatial topos

answered Nov 26, 2022 at 3:41

12 votes

Tight apartness relations in toposes

answered Feb 23, 2020 at 15:41

11 votes

What does the Zariski topos of $\mathbb{P}^1$ classify?

answered May 13, 2017 at 21:06

11 votes

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Constructive proof that a kernel consists of nilpotent elements

answered Sep 22, 2016 at 15:53

11 votes

Accepted

Properties of the petit Zariski topos

answered Oct 13, 2016 at 8:24

10 votes

Alternate proofs of Hilberts Basis Theorem

answered Feb 10, 2016 at 14:09

9 votes

When can we prove constructively that a ring with unity has a maximal ideal?

answered Jan 27, 2023 at 1:00

8 votes

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Points of the big Zariski site

answered Sep 14, 2018 at 0:10

7 votes

Accepted

Classifying Space of "Valuation Ringed Spaces over a Topos"

answered Apr 30, 2019 at 12:01

7 votes

Is there a correction to the failure of geometric morphisms to preserve internal homs?

answered Apr 25 at 20:25

6 votes

Construction of the petit Zariski topos out of the gros topos of a scheme

answered May 1, 2019 at 17:56

6 votes

Constructively, is the unit of the “free abelian group” monad on sets injective?

answered Jun 11, 2018 at 15:14

6 votes

Grothendieck spectral sequence and Mayer-Vietoris sequence

answered Jan 17, 2015 at 14:54

6 votes

What is the functor tensor product?

answered May 2, 2015 at 17:53

5 votes

Is there a universal property for graded localization?

answered Sep 5, 2016 at 20:39

5 votes

Tweetable Mathematics

answered Apr 30, 2017 at 11:07

5 votes

What does overtness mean for metric spaces?

answered Oct 11, 2021 at 9:22

4 votes

constructive Serre classes

answered Feb 10, 2016 at 23:49

4 votes

The upper semi-continuous rank of a module sheaf

answered Feb 7, 2013 at 13:19

4 votes

Pure first order logic formulations of Markov's principle

answered Nov 30, 2016 at 10:10

3 votes

Topos theory reference suitable for undergraduates

answered May 3, 2017 at 13:24

3 votes

Does 'finite + finitely presented as an algebra' equal 'finitely presented as a module'?

answered May 22, 2017 at 18:57

3 votes

Can the methods of classical algebraic geometry be made rigorous with a synthetic approach?

answered Oct 15, 2018 at 14:17

3 votes

What does an ideal correspond to in the internal language of sheaves?

answered Nov 13, 2018 at 13:56

3 votes

Explaining the consistency of PRA and ZF from predicative foundations

answered Jan 20 at 5:13

2 votes

Accepted

W-types and inverse image functor

answered Feb 18, 2023 at 1:18

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32 Answers

Joyal's construction of the spectrum of a commutative ring

Is the theory of vector bundles just linear algebra done in a suitable topos?

Locales as spaces of ideal/imaginary points

Do pretopoi have cohomology and homotopy groups?

Examples of statements that are valid in every spatial topos

Tight apartness relations in toposes

What does the Zariski topos of $\mathbb{P}^1$ classify?

Constructive proof that a kernel consists of nilpotent elements

Properties of the petit Zariski topos

Alternate proofs of Hilberts Basis Theorem

When can we prove constructively that a ring with unity has a maximal ideal?

Points of the big Zariski site

Classifying Space of "Valuation Ringed Spaces over a Topos"

Is there a correction to the failure of geometric morphisms to preserve internal homs?

Construction of the petit Zariski topos out of the gros topos of a scheme

Constructively, is the unit of the “free abelian group” monad on sets injective?

Grothendieck spectral sequence and Mayer-Vietoris sequence

What is the functor tensor product?

Is there a universal property for graded localization?

Tweetable Mathematics

What does overtness mean for metric spaces?

constructive Serre classes

The upper semi-continuous rank of a module sheaf

Pure first order logic formulations of Markov's principle

Topos theory reference suitable for undergraduates

Does 'finite + finitely presented as an algebra' equal 'finitely presented as a module'?

Can the methods of classical algebraic geometry be made rigorous with a synthetic approach?

What does an ideal correspond to in the internal language of sheaves?

Explaining the consistency of PRA and ZF from predicative foundations

W-types and inverse image functor