 The database has been maintained for over twenty years (the first proofs in "set.mm" are dated August 1993).The database contains developments, among other fields, of set theory (ordinals and cardinals, recursion, equivalents of the axiom of choice, the continuum hypothesis...), the construction of the real and complex number systems, order theory, graph theory, abstract algebra, linear algebra, general topology, real and complex analysis, Hilbert spaces, number theory, and elementary geometry.This database was first created by Norman Megill, but as of 2019-10-04 there have been 48 contributors (including Norman Megill).