David Roberts Grothendieck pretopology

This is to gather examples.

• $\mathcal{O}$ is the pretopology of open covers
• $\mathcal{N}$ is the pretopology of numerable covers
• $os$ is the pretopology of open surjections
• (more…)

Created on October 1, 2009 at 12:10:08. See the history of this page for a list of all contributions to it.