MSU's Mathematics collection levels are found here. ALA defines collection levels as follows:
Minimal Level: A subject area in which few selections are made beyond very basic books.
Basic Information Level: A collection of up-to-date general materials that serves to introduce and define a subject.
Instructional Support Level: A collection that is closely tied to the needs of the curriculum:A. Undergraduate Support level: a collection that is adequate to support undergraduate instruction.
Research Level: A collection that includes major published source materials required for research needs.
Comprehensive level: A collection in which the Library includes all significant works of recorded knowledge for a necessarily defined and limited field.
The Mathematics collection levels are currently primarily at 3A and 3B with a few approaching 4. MSU does not attempt to collect at intensity levels of 4 or above, since the mathematics collection at the University of Illinois is rated at a 5 -- Comprehensive Level, and considered a regional resource center in the Research Libraries Group.