An update for Grassmannian.info: exceptional collections
Lockdown is good for developing mathematical websites, I guess. I've pushed another update to grassmannian.info: it now shows some basic information about the derived categories of generalised Grassmannians, namely when it is known that a full exceptional collection exists. An important folklore conjecture states that this is the case, but as you can see when you enable the coloring in the table, we are still a long way off of settling it.
What I never realised is that, out of all known cases, only one is not (co)minuscule or (co)adjoint. These are somehow the easiest varieties, and for the majority of them (see below) a full exceptional collection is known. The unique example outside this class is constructed by Guseva in On the derived category of $\mathrm{IGr}(3,8)$ (denoted $\mathrm{SGr}(3,8)$ on grassmannian.info.
Out of the (co)minuscule or (co)adjoint varieties, the ones for which an exceptional collection is not yet constructed are:
- the (co)adjoint in type E6: E6/P2
- the (co)minuscule in type E7: the Freudenthal variety, or E7/P7
- the (co)adjoint in type E7: E7/P1
- the (co)adjoint in type E8: E8/P8
- the adjoint in type F4: F4/P1
If you manage to construct an exceptional collection in one of these cases, I will give you a large bar of your preferred Belgian chocolate, if you need some further incentive to think about it.
I've also completed copying the information from Bourbaki's appendix.