[rocqua]

When I have discussed this, most people I know argued the opposite (for Mathematics). The undergrad courses are supposed to lay the foundation. Stuff you need so often, and stuff you need to recognize when useful, you should know it by heart.

At graduate level, there is too much stuff. You know the outline, you know where to find stuff. But you don't need to know everything exactly. If you forgot one passage from a definition, that should not cause a failure. Because in 'real Mathematics' you get to look at references.

A nice trick for open book is to make it time-infeasible to just look up everything. But allow students access to the materials incase they have a brainfart.