mini - two days, typically but not necessarily, over a weekend where
one or two topics (say, automata theory and computability, or algorithms and
data structures) is covered by two speakers. The course should be for a
minimum of five hours.
short - six days, where two to four topics is covered by two to four
speakers.
long - three weeks, where four to six topics (along a particular theme,
say theoretical computer science) is covered by up to eight speakers.