A λ-unifiability test for set theory

We present a semi-decision algorithm for the unifiability of two set-theoretic formulas modulo -reduction. The algorithm is based on the approach developed by G. Huet for type theory, but requires additional measures because formulas in set theory are not all normalizable. We present the algorithm in an Ada-like pseudocode, and then prove two theorems that show the completeness and correctness of the procedure. We conclude by showing that -unification is not a complete quantifier substitution method for set theory-unlile first-order unification and first-order logic. In this respect set theory is similar to type theory (higher-order logic).This material is based upon work supported by the National Science Foundation under award number ISI-8560438. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author and do not necessarily reflect the views of the National Science Foundation.     

基于合一的链接文法

以词汇主义形式语法为基础,建立了链接文法与合一理论相结合的句法分析新方法.在封闭测试中,基于合一的链接文法句法分析精确率和召回率相比传统链接文法分别提高了9.6%和14.1%.实验表明方法具有一定独创性和高效性.     

电力企业IT运维生产化探讨

分析目前电力企业IT运行存在的问题,探讨IT运维生产化的主要管理流程,并从管理和技术手段两方面提出初步的解决方案.     

矿业可持续发展的基本途径探讨

矿业可持续发展是许多矿业大国必须面临的重要课题。本文认为，矿业可持续发展的基本途径在于矿产资源环境一体化体系的建立，矿工素质和生活质量持续提高，非传统矿产资源勘查和替代资源的开发利用。     

三维曲面工件形状的归一化测量方法

介绍了一种全新的三维曲面工件形状的归一化测量方法，通过测量工件曲面上的若干条截面曲线的曲率函数而测得曲面工件的三维形状，并且验证了测量方法的实用可行性。     

诠释包装设计之 “无形"理念

“无形”是包装之极,“无形”包装设计理念是设计内容与形式的完善协调,是设计整体,醒目的视觉效应,是设计艺术与印刷技术的统一,是民族文化与艺术的交融。     

Solving equations with sequence variables and sequence functions

Term equations involving individual and sequence variables and sequence function symbols are studied. Function symbols can have either fixed or flexible arity. A sequence variable can be instantiated by any finite sequence of terms. A sequence function abbreviates a finite sequence of functions all having the same argument lists. It is proved that solvability of systems of equations of this form is decidable. A new unification procedure that enumerates a complete almost minimal set of solutions is presented, together with variations for special cases. The procedure terminates if the solution set is finite. Applications in various areas of artificial intelligence, symbolic computation, and programming are discussed.     

基于空间场屏蔽效能测试方法研究

基于空间电磁场屏蔽效能测试中,目前存在着各种测试标准,虽然每种方法都能获得实验数据,但是不同测试方法下的实验数据差异性很大,不具有可比性。针对以上问题,该文对各种方法的选用、原理以及优缺点展开详细的研究和分析,并对基于空间电磁场屏蔽效能测试方法标准的统一性和规范化做了相应的建议和尝试,来优化和控制屏蔽部件、屏蔽材料和屏蔽实体的屏蔽效能测试,使测试标准更加符合实际测试和生产实践。     

An Empirical Approach to Spanish Anaphora Resolution

This paper documents the development of an empirically-basedsystem implemented in Prolog that automatically resolves severalkinds of anaphora in Spanish texts. These are pronominalreferences, surface-count anaphora, one-anaphora and ellipticalzero-subject constructions (i.e., sentences that omit theirpronominal subject). The resolution is based onrepresentations resulting from either partial or full parsing. Thesystem developed can also work on the output of a POStagger or with different dictionaries, without changing thegrammar. This grammar represents the syntactic information of eachlanguage by means of the Slot Unification Grammar formalism. The different kinds of information used for anaphora resolution in full and partial parsing are shown, as wellas evaluation results. The system has been adapted toEnglish texts, obtaining encouraging results that prove that itcan be applied with only a very few refinements to other languagesas well as Spanish and English. In addition, the differencesbetween English and Spanish anaphora are noted.     

Complexity of unification problems with associative-commutative operators

The unification problem for terms containing associative and commutative functions is of importance in theorem provers based on term rewriting and resolution methods as well as in logic programming. The complexity of determining whether two such terms are unifiable was known to be NP-hard. It is proved that the problem is NP-complete by describing a nondeterministic polynomial time algorithm for it. The case where the terms are linear and have no common variables is shown to be in P. The NP-completeness of other similar unification problems, in particular, when a function symbol is also idempotent and/or has a unit (identity), is also discussed. Finally, a table of the complexity of E-matching and E-unification problems is given.Partially supported by the National Science Foundation grant nos. DCR-8408461 and CCR-8906678. A preliminary version of this paper appeared earlier as a technical report of General Electric Corporate Research and Development, Dec. 1986.