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This question is related to this one: Local smallness and (higher) topoiLocal smallness and (higher) topoi which has not yet been answered.

The $2$-category of topoi and geometric morphisms is not locally small. (As I mentioned in the question above, for example, if $A$ is the classifying topos for abelian groups, the category of geometric morphisms from $Set$ to $A$ is equivalent to the category of all abelian groups, which is not small.)

**Question:**Is the $2$-category of topoi and only etale geometric morphisms locally small?

Note: I'm actually interested in the corresponding statement for infinity topoi.

Remark: Notice that this $2$-category is locally a topos, so, it is locally locally small (sorry for the weird wording). That is, if $E$ is a topos, the slice 2-cat over $E$ consisting of etale morphisms over $E$ is known to be equivalent to $E$ itself (and hence is really a 1-category). There is a corresponding result for infinity topoi as well. Perhaps there is a way to use this to prove the result.

This question is related to this one: Local smallness and (higher) topoi which has not yet been answered.

The $2$-category of topoi and geometric morphisms is not locally small. (As I mentioned in the question above, for example, if $A$ is the classifying topos for abelian groups, the category of geometric morphisms from $Set$ to $A$ is equivalent to the category of all abelian groups, which is not small.)

**Question:**Is the $2$-category of topoi and only etale geometric morphisms locally small?

Note: I'm actually interested in the corresponding statement for infinity topoi.

Remark: Notice that this $2$-category is locally a topos, so, it is locally locally small (sorry for the weird wording). That is, if $E$ is a topos, the slice 2-cat over $E$ consisting of etale morphisms over $E$ is known to be equivalent to $E$ itself (and hence is really a 1-category). There is a corresponding result for infinity topoi as well. Perhaps there is a way to use this to prove the result.

This question is related to this one: Local smallness and (higher) topoi which has not yet been answered.

The $2$-category of topoi and geometric morphisms is not locally small. (As I mentioned in the question above, for example, if $A$ is the classifying topos for abelian groups, the category of geometric morphisms from $Set$ to $A$ is equivalent to the category of all abelian groups, which is not small.)

**Question:**Is the $2$-category of topoi and only etale geometric morphisms locally small?

Note: I'm actually interested in the corresponding statement for infinity topoi.

Remark: Notice that this $2$-category is locally a topos, so, it is locally locally small (sorry for the weird wording). That is, if $E$ is a topos, the slice 2-cat over $E$ consisting of etale morphisms over $E$ is known to be equivalent to $E$ itself (and hence is really a 1-category). There is a corresponding result for infinity topoi as well. Perhaps there is a way to use this to prove the result.

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David Carchedi
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This question is related to this one: Local smallness and (higher) topoi which has not yet been answered.

The $2$-category of topoi and geometric morphisms is not locally small. (As I mentioned in the question above, for example, if $A$ is the classifying topos for abelian groups, the category of geometric morphisms from $Set$ to $A$ is equivalent to the category of all abelian groups, which is not small.)

**Question:**Is the $2$-category of topoi and only etale geometric morphisms locally small?

Note: I'm actually interested in the corresponding statement for infinity topoi.

Remark: Notice that this $2$-category is locally a topos, so, it is locally locally small (sorry for the weird wording). That is, if $E$ is a topos, the slice 2-cat over $E$ consisting of etale morphisms over $E$ is known to be equivalent to $E$ itself (and hence is really a 1-category). There is a corresponding result for infinity topoi as well. Perhaps there is a way to use this to prove the result.

This question is related to this one: Local smallness and (higher) topoi which has not yet been answered.

The $2$-category of topoi and geometric morphisms is not locally small. (As I mentioned in the question above, for example, if $A$ is the classifying topos for abelian groups, the category of geometric morphisms from $Set$ to $A$ is equivalent to the category of all abelian groups, which is not small.)

**Question:**Is the $2$-category of topoi and only etale geometric morphisms locally small?

Note: I'm actually interested in the corresponding statement for infinity topoi.

This question is related to this one: Local smallness and (higher) topoi which has not yet been answered.

The $2$-category of topoi and geometric morphisms is not locally small. (As I mentioned in the question above, for example, if $A$ is the classifying topos for abelian groups, the category of geometric morphisms from $Set$ to $A$ is equivalent to the category of all abelian groups, which is not small.)

**Question:**Is the $2$-category of topoi and only etale geometric morphisms locally small?

Note: I'm actually interested in the corresponding statement for infinity topoi.

Remark: Notice that this $2$-category is locally a topos, so, it is locally locally small (sorry for the weird wording). That is, if $E$ is a topos, the slice 2-cat over $E$ consisting of etale morphisms over $E$ is known to be equivalent to $E$ itself (and hence is really a 1-category). There is a corresponding result for infinity topoi as well. Perhaps there is a way to use this to prove the result.

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David Carchedi
  • 15.5k
  • 38
  • 99

Are topoi and etale geometric morphisms locally small?

This question is related to this one: Local smallness and (higher) topoi which has not yet been answered.

The $2$-category of topoi and geometric morphisms is not locally small. (As I mentioned in the question above, for example, if $A$ is the classifying topos for abelian groups, the category of geometric morphisms from $Set$ to $A$ is equivalent to the category of all abelian groups, which is not small.)

**Question:**Is the $2$-category of topoi and only etale geometric morphisms locally small?

Note: I'm actually interested in the corresponding statement for infinity topoi.