nLab plus construction


The terminology ‘plus construction’ is used for three very different types of construction.

  • The version which sends a presheaf to a separated presheaf to a sheaf is described at plus construction on presheaves and sheaf.

  • The process of killing a perfect normal subgroup of the fundamental group of a space is described under Quillen plus construction.

  • The assignment, due to John Baez and James Dolan, OO +O \mapsto O^+ sending a operad (with colours SS) to a new operad whose algebras are SS-coloured operads equipped with an operad morphism to OO (i.e. slices over OO).


Last revised on June 8, 2023 at 14:26:36. See the history of this page for a list of all contributions to it.