mathlib3 documentation

category_theory.sites.spaces

Grothendieck topology on a topological space #

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Define the Grothendieck topology and the pretopology associated to a topological space, and show that the pretopology induces the topology.

The covering (pre)sieves on X are those for which the union of domains contains X.

Tags #

site, Grothendieck topology, space

References #

Implementation notes #

We define the two separately, rather than defining the Grothendieck topology as that generated by the pretopology for the purpose of having nice definitional properties for the sieves.

The Grothendieck topology associated to a topological space.

Equations

The Grothendieck pretopology associated to a topological space.

Equations
@[simp]

The pretopology associated to a space is the largest pretopology that generates the Grothendieck topology associated to the space.

@[simp]

The pretopology associated to a space induces the Grothendieck topology associated to the space.