Redirect to:

This page is a redirect. The following categories are used to track and monitor this redirect:

From a subtopic: This is a redirect from a subtopic of the target article or section.
- If the redirected subtopic could potentially have its own article in the future, then also tag the redirect with {{R with possibilities}} and {{R printworthy}}.

To a section: This is a redirect from a topic that does not have its own page to a section of a page on the subject. For redirects to embedded anchors on a page, use {{R to anchor}} instead.

When appropriate, protection levels are automatically sensed, described and categorized.

Principal congruence subgroup