A MACHINE-ORIENTED LOGIC BASED ON RESOLUTION PRINCIPLE
A MACHINE-ORIENTED LOGIC BASED ON RESOLUTION PRINCIPLE
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DOI:
10.1145/321250.321253
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发表时间:
1965-01-01
影响因子:
2.5
通讯作者:
ROBINSON, JA
中科院分区:
文献类型:
--
作者:
ROBINSON, JA
Argonne Nalionrd Laboratory* and t~ ice U. niver~ itg~: tb.~ tract. Theorem-proving on the computer, using procedures based on the fund~-mental theorem of Herbrand concerning the first-order predicate etdeulus, is examined with~ view towards improving the efticieney and widening the range of practical applicability of these procedures. A elose analysis of the process of substitution (of terms for variables), and the process of truth-functional analysis of the results of such substitutions, reveals that both processes can be combined into a single new process (called resolution), iterating which is vastty more ef [ieient than the older cyclic procedures consisting of substitution stages alternating with truth-functional analysis stages. The theory of the resolution process is presented in the form of a system of first<~ rder logic with. just one inference principle (the resolution principle). The completeness of the system is proved; the simplest proof-procedure based oil the system is then the direct implementation of the proof of completeness. Howew~ r, this procedure is quite inefficient,~ nd the paper concludes with a discussion of several principles (called search principles) which are applicable to the design of efficient proof-procedures employing resolution as the basle logical process.1. introductionPresented in this paper is a formulation of first-order logic which is specifically designed for use as the basle theoretical instrument of a computer theoremproving program. Earlier theorem-proving programs have been based oil systems of first-order logic which were originally devised for other purposes. A prominent feature of those systems of logic, which is l~ eking in the system described in this paper, is the relative, simplicity of their inference principles. Traditionally, a sirlgle step in a deduction has bee~ required, for pragmatic a,~ d psychological reasons, to be simple enough, broadly speaking, to be apprehended as correct by a human being in a single intellectual act. No doubt this custom origiu~ tes i~ 1 the desire that each single step of a deduction should be indubitable, even though the deduction as a whole may consist of a long chain of such steps. The ultimate conclusion of a deduction, if the deduction is correct, follows logie~ dly from the premisses used ia tile deduction; but the human mind may well fit~ d the unmediated transition from the prelnisses to the conclusion surprising, hence (psychologically) dubitable. Part of the point, theft, of the logical analysis of deductive reasoning has been to reduce complex inferences, which are beyond the capacity of the human mind to grasp as single steps, to chains of simpler inferences, each of which is within the capacity of the human milld to grasp as a single transactiom