一、引言《管理现代化》杂志,1989年第4期刊载了张国旺、李长青同志的文章:《计划评审技术中工程网络图赶工及优化问题新探》。在该文中,作者提出了负时差消除定理,并举例用负时差消除定理进行工程网络图赶工及优化设计。其消除定理是这样叙述的:“在工程网络 I. INTRODUCTION The magazine “Management Modernization” was published in the fourth issue of 1989 with the article by Zhang Guowang and Li Changqing: “A New Probe into the Time-Consolidation and Optimization of Engineering Network Diagram in Planning Review Technology”. In this paper, the author proposes a negative time difference elimination theorem, and uses the negative time difference elimination theorem to carry out construction network engineering and optimization design. The elimination theorem is described as follows: "In engineering networks