  Algorithmic education theory examines, among other things, the trade-off
between reviewing old material and studying new material: time spent learning
the new comes at the expense of reviewing and solidifying one's understanding
of the old. This trade-off is captured in the `Slow Flashcard System' (SFS) --
a system that has been studied not only for its applications in educational
software but also for its critical properties; it is a simple discrete
deterministic system capable of remarkable complexity, with standing
conjectures regarding its longterm behavior. Here we introduce a probabilistic
model of SFS and further derive a continuous time, continuous space PDE model.
These two models of SFS shed light on the longterm behavior of SFS and open new
avenues of research.
