Abstract: In this paper, the critical activities decomposition paradox and the total floats paradox in the traditional algorithm of GPRs multi-time difference network are found. The critical activities decomposition paradox is that the critical activity which is decomposed into two activities with FTS=0 logical relation will lead to the total duration shortened. The total floats paradox is that activities which are decomposed will increase the total float. The reasons of these two paradoxes and propose critical activities decomposition optimization theorem and total float decomposition optimization theorem are analyzed. The new methods make the total project duration and the distribution of total time of the network optimized. They can also provide more scientific and sufficient conditions for project WBS and resource optimization. In addition the division optimization theorem is combined with the flow process network in order to provide a scientific optimization method for the construction section in the flow process.

Key words: GPRs network, division paradox, division optimization theorem, the flow process network