A project having of a set of jobs and a set of precedences, where precedence (i; j) show that job j cannot begin before job i is completed. Let c_{i} be the duration of job i. We wish to find the least possible duration of the project.
(a) Formulate an (minimization) LP for this problem. Declare the meaning of all variables that you use. It is useful to introduce two artificial jobs s and t, each of zero duration, where s is the first job done and t is the last job done