nLab
negative moment

Contents

Idea

In the context of idempotent (∞,1)-monads or comonads, or moments, the negative moment is the homotopy fiber of the unit or homotopy cofiber of the counit.

These are denoted, e.g., ¯\overline{\sharp}, ¯\overline{\flat}.

  • The negative of idid (both as monad and comonad) is *\ast.
  • The negative of *\ast is idid.
  • The negative of \emptyset is the maybe monad, although not itself idempotent, so not a moment.

Last revised on September 26, 2016 at 06:49:53. See the history of this page for a list of all contributions to it.