A note on the categorical van Kampen Theorem

作者：Clementino Maria Manuel^*

来源：Topology and Its Applications, 2011, 158(7): 926-929.

DOI：10.1016/j.topol.2011.01.011

• Effective descent morphism
• Triquotient map
• Van Kampen Theorem

In this note we show that for the canonical map X(1) + X(2) -> X, from the topological sum of two subspaces X(1), X(2) of X into X, to be of effective descent it is sufficient to be hereditarily a quotient map. Further, making use of the Brown-Janelidze categorical van Kampen Theorem, this translates into a van Kampen-type result.

• 出版日期2011-4-15