I have encountered this problem in a management paper...Here 'a' and 'p' are two group of jobs and b is a job in group 'a' and 'q' is job in group 'p'. They have defined the set "R' just to say that all the terms a,b,p,q are members of "R".. But what does the set physically mean?? pls help
is it related to arrival time of groups?? is it saying that group "a" arrived before "p" and if they both arrive together job "b" is processed before "q"?