Conferred property values can be changed or "erased" when, after the topic map graph has been altered, conferred property values are recalculated, and a node's situation no longer requires one of its properties to have the value that had been conferred upon it on account of its previous situation (see REF: parid0429 6.3). By contrast, as specified in REF: parid0245 4.7.1 (above), built-in values cannot be changed or erased.

should be treated under definition of conferred values, perhaps
even so far as to state that since the value is conferred by a
situation, then if the situation changes, the value may, or may not change