| mb nat | Material pertaining to natural numbers as opposed to integers generally. |
| mb basic | Basic generally useful devices. |
| sqequal 1 | |
| rel 1 | Common properties of binary relations. |
| list 1 | |
| int 2 | |
| bool 1 | |
| int 1 | |
| well fnd | |
| fun 1 | |
| core | Some basic concepts defined type-theoretically. |