22. A case-based reasoning system, comprising a rule base having a plurality of inferential rules; a case base having a plurality of exemplar cases; a data base having a plurality of data records having a plurality of data items external to a set of facts in a problem template and external to a set of derived facts concluded from said set of facts; an inference engine comprising means for performing case-based reasoning steps on said cases and said problem template, and comprising means for performing rule-based reasoning steps on said data items external to said set of facts in said problem template and external to said derived facts using said rules in a unified automated reasoning system; wherein said inference engine comprises means for matching said problem template having a set of facts to said case base; and means for applying said rules to said cases, said data items in said data records external to said set of facts in said problem template and external to said derived facts, and said facts in said problem template; and means for performing a method of matching a problem template to a case base, said method comprising the steps of first generating a set of signature bits in response to at least one attribute-value pair for each case in said case base; second generating a set of signatures, one for each said case, in response to said set of signature bits; recording a signature file having at least one mapping from said set of signatures to said cases; third generating a set of test bits for said problem template; and searching said signature file in response to said test bits.
22. A case-based reasoning system, comprising a rule base having a plurality of inferential rules; a case base having a plurality of exemplar cases; a data base having a plurality of data records having a plurality of data items external to a set of facts in a problem template and external to a set of derived facts concluded from said set of facts; an inference engine comprising means for performing case-based reasoning steps on said cases and said problem template, and comprising means for performing rule-based reasoning steps on said data items external to said set of facts in said problem template and external to said derived facts using said rules in a unified automated reasoning system; wherein said inference engine comprises means for matching said problem template having a set of facts to said case base; and means for applying said rules to said cases, said data items in said data records external to said set of facts in said problem template and external to said derived facts, and said facts in said problem template; and means for performing a method of matching a problem template to a case base, said method comprising the steps of first generating a set of signature bits in response to at least one attribute-value pair for each case in said case base; second generating a set of signatures, one for each said case, in response to said set of signature bits; recording a signature file having at least one mapping from said set of signatures to said cases; third generating a set of test bits for said problem template; and searching said signature file in response to said test bits. 33. A system as in claim 22, wherein a set of cases which are matched are recorded in a match table.