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Elementary topos nonsense #411
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oh, she's alive! |
What needs to be done to take this out of draft status? Working on injective objects right now, and I'd like to show that every subobject classifier is injective 🙂 |
I guess what's here is mostly done, there's just not a lot of it |
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Looks great, only have a couple of minor nits.
It would also be cool to prove that the displayed category of subobjects has a skeletal generic object iff it has a subobject classifier, but that could be done in a separate PR.
$\name{A} : A \to \Omega$ into the presheaf of sieves on $\cC$ is valued | ||
in closed sieves. | ||
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First, suppose that the domain of $A' \mono A$ is indeed a sheaf. First, |
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Two "First,"s in a row.
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why after you're done assuming the other thing is the new first thing to do!
We can then compute, in $\psh(\cC)$, the name of $A'$, resulting in a | ||
natural transformation $\name{A'} : A \to \Omega$. It remains to show | ||
that this transformation is actually valued in $\Omega_J$, i.e. that | ||
each of the resulting sieves is closed. To this end, susppose we have |
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each of the resulting sieves is closed. To this end, susppose we have | |
each of the resulting sieves is closed. To this end, suppose we have |
watch this space but not too closely