Cosheaf
Appearance
In topology, a branch of mathematics, a cosheaf with values in an ∞-category C that admits colimits is a functor F from the category of open subsets of a topological space X (more precisely its nerve) to C such that
- (1) The F of the empty set is the initial object.
- (2) For any increasing sequence of open subsets with union U, the canonical map is an equivalence.
- (3) is the pushout of and .
The basic example is where on the right is the singular chain complex of U with coefficients in an abelian group A.
Example:[1] If f is a continuous map, then is a cosheaf.
See also
Notes
References
- http://www.math.harvard.edu/~lurie/282ynotes/LectureVIII-Poincare.pdf
- http://arxiv.org/pdf/1303.3255v1.pdf , section 3, in particular Thm 3.10 p.34