Canonicalizer proper

The Canonicalizer proper is the main part of the Canonicalization subsystem: the part of the Cyc system that takes in EL expressions and converts them to HL expressions.

1. Two different, but logically equivalent, CycL sentences are transformed into the same HL sentence by the Canonicalizer.
2. On its way to being stored in the Cyc KB, a CycL sentence that is asserted passes through the Canonicalizer, which can re-order arguments of commutative relations, re-order the literals of rules, and perform various other rewrites to assure that (1), above, holds.
3. On its way to being processed by the Cyc Inference Engine, a CycL query sentence passes through the Canonicalizer, which performs the rewrites mentioned above and also replaces CycL variables like ?X, ?THING and so forth with inference variables like ?var0, ?var1, etc.