nLab redirect

Instiki now includes the ability to redirect pages.

Example: Plural nouns and capitalization

To redirect the plural

[[categories]]

to the existing page

[[category]]

simply edit category and insert

[[!redirects categories]]

at the bottom of the page. From then on, whenever you link to categories, you are taken to category. This saves you the headache of typing things like

[[category|categories]]

For example, if you open category for editing and look at the bottom, you will find

[[!redirects categories]]
[[!redirects Category]]
[[!redirects Categories]]

Therefore, categories, Category, and Categories all redirect to category now.

Caveat

Redirects only work if the desired redirected page [[categories]] does not already exist.

Don’t worry, this is a feature, not a bug, designed to avoid silly things like infinite redirect loops, etc.

In the event that [[categories]] does exist already, then it probably should not if [[category]] already exists.

If you run into this situation, you can help by transferring material from [[existing pages]] to [[existing page]] and change the name of [[existing pages]] to [[existing pages > history]]. Now the redirects will work and we maintain the history of any revisions that were made to [[existing pages]].

Example: Links with non-ASCII symbols

Currently, there are many pages with titles that would ideally include symbols, e.g. (infinity,1)-category.

Prior to redirects, if you wanted to link to this page, you could either write the ugly version

[[(infinity,1)-category]]

or worse, if you were using the plural version you could write

[[(infinity,1)-category|(infinity,1)-categories]]

Alternatively, you could get a little fancy with

$(\infty,1)$-[[(infinity,1)-category|(infinity,1)-categories]]

which preserves the distinction between math and text but doesn’t allow the link to cover the entire linking phrase.

Currently, if you open (infinity,1)-category for editing and look at the bottom, you will see

[[!redirects (∞,1)-category]]
[[!redirects (∞,1)-categories]]
[[!redirects (infinity,1)-categories]]

This means that we can now simply insert links like (∞,1)-categories and be redirected to (infinity,1)-category. The only downside here (compared to the previous alternative) is that math material is in the text font. (Some of us even write $2$-[[2-category|category]] for this reason.)

Caveat

The ∞ symbol included in the link is not obtained via the itex syntax $\infty$. To actually include non-ASCII symbols in links, you either need to be an expert at unicode or simply find the ‘∞’ symbol already displayed somewhere, copy it, and paste the symbol into the edit box. To see what I mean, you can edit this page to look at the source code for the link: (∞,1)-categories.

Undoing a Redirect

Occasionally you may come across a situation where a redirect exists for a link that you’d like to create a separate entry for. For example, constructivism is currently redirected to constructive mathematics. If you’d prefer to have a separate entry for constructivism (to discuss the philosophy rather than the mathematical practice), you can simply edit constructive mathematics and remove the line (likely at the bottom of the edit box)

[[!redirects constructivism]]

Now you can create constructivism as usual and any pages that had previously been redirected to constructive mathematics will now point to your new entry.

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See also the official Instiki guidelines on redirects.