Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options questions only not deleted user 49

Questions taking place in the category of locales, which is given by the opposite of the category of frames. Also appropriate for questions about pointless topology.

5 votes
1 answer
197 views

Topological regularity for toposes

Often, topological properties of locales can be generalized naturally to toposes (or, often, to geometric morphisms). … Is there a notion of "regularity" for toposes that generalizes the topological notion of regularity for spaces and locales? …
Mike Shulman's user avatar
  • 66.8k
8 votes
1 answer
209 views

Detecting positive endomaps of the formal reals

Locales are often better-behaved than topological spaces in constructive mathematics (i.e. in the absence of the law of excluded middle). … My question is: suppose $f:R_f \to R_f$ is a continuous map of locales, such that $f(x)>0$ for all points $x$ of $R_f$ (i.e. for all actual real numbers $x$); does it follow (constructively) that $f$ factors …
Mike Shulman's user avatar
  • 66.8k
15 votes
1 answer
1k views

The real numbers object in Sh(Top)

If $X$ is a sober topological space, the real numbers object in the topos $\mathrm{Sh}(X)$ is the sheaf of continuous real-valued functions on $X$. This is proven very explicitly in Theorem VI.8.2 of …
Mike Shulman's user avatar
  • 66.8k
16 votes
1 answer
566 views

Do strict pro-sets embed in locales?

Can "strict pro-sets" be identified with "pro-discrete locales"? Note that some hypothesis such as "surjective transition maps" is necessary. … For instance, the pro-set $\cdots \xrightarrow{+1} \mathbb{N} \xrightarrow{+1} \mathbb{N} \xrightarrow{+1} \mathbb{N}$ is not isomorphic to the trivial pro-set ∅, but its limit in the category of locales
Mike Shulman's user avatar
  • 66.8k