Can anybody provide me references on theorems and proofs on makespan bounds of optimally scheduled DAG for following this basic problem: assume DAG with deterministic execution time and zero communication costs have optimum (minimum) makespan Cmax,opt for unlimited number of resources (processors). Now replace any task T (execution time t) by multiple serially connected tasks T(i) with same sum execution time as the original task i.e. sum{t(i)}=t resulting in DAG' and optimum makespan C'max,opt for an unlimited number of processors. What parts of the following relation are valid: a) C'max,opt