1. A computer comprising a semantic network stored in its accessible memory, said semantic network comprising semantic network elements, the computer comprising: a first omission rule means; and a first index maintainer responsive to the first omission rule means, the omission rule means causing the first index maintainer to omit at least one link referencing a first node from a first index associated with the first node.
1. A computer comprising a semantic network stored in its accessible memory, said semantic network comprising semantic network elements, the computer comprising: a first omission rule means; and a first index maintainer responsive to the first omission rule means, the omission rule means causing the first index maintainer to omit at least one link referencing a first node from a first index associated with the first node. 9. The computer of claim 1 , further comprising an omission rule learner configured to modify at least one omission rule.