PERT & CPM
PERT - Program Evaluation and Review Technique
The program (or project) evaluation and review technique (PERT) is a statistical tool used in project management, which was designed to analyze and represent the tasks involved in completing a given project.
https://en.wikipedia.org/wiki/Program_evaluation_and_review_technique
CPM - Critical Path Method
The critical path method (CPM), orcritical path analysis (CPA), is an algorithm for scheduling a set of project activities.It is commonly used in conjunction with the program evaluation and review technique (PERT). A critical path is determined by identifying the longest stretch of dependent activities and measuring the time required to complete them from start to finish.