## More Information About Assertions

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The symbols before an assertion also carry information about the truth value of the assertion:

: False assertion
: Monotonically true GAF
: Asserted default true GAF
: Deduced default true GAF

See "Truth Values" in "The Syntax of CycL" for more on truth values in Cyc®.

If an assertion is present in the KB because it is the result of inference, it is generally preceded by the fourth symbol above (i.e. the symbol for deduced default true GAF). These assertions are called remote or inferred assertions.

If an assertion has been directly asserted (by some editing operation) into the knowledge base, it is preceded by one of the other three color symbols above if it is a GAF. Such assertions are called local assertions.

If an assertion is both local and inferred, it is referred to as redundant. Such redundant default true GAF's are usually preceded by this symbol:

Assertions referred to as "HL" inferred, indicates that the assertions exist "virtually" in the KB, recomputed on demand by a Heuristic Level (HL) module -- a specialized piece of code that efficiently performs a particular kind of inference. For example, there is one module that takes care of the transitivity of #$genls (i.e., ensures that if (#$genls A B) and (#$genls B C), then (#$genls A C)).

In certain cases, a local assertion may be marked as redundant using this symbol:

This means that an HL module has concluded that even if the local assertion were removed from the KB, the HL module would conclude its existence anyway.

The majority of cases which are currently marked in this fashion are #$genls and #$isa assertions.

Notice the locally-asserted genls of #$TeethCleaning (there should be two). These are the closest, or most-specific, supersets of #$TeethCleaning.

Last Update: 03/22/2002 11:42:06