Update 'doc.md'

doc.md

@@ -28,7 +28,7 @@ Both operations require that the start times are recomputed.
 ## constraints
   - only schedule new $\tau$ if another $\tau$ is finished
   - only schedule $\tau \in T_k$ that has no unscheduled predecessor in $T_k$
-  - only one job on a machine any given time
+  - only one task on a machine any given time
 
 ## implementation in Python
   - translate problem into list of jobs, jobs into lists of tasks, ie problem = [$T_0, T_1,\dots,T_{k-1}$], $T_i$ = [$\tau_1,\tau_2,\dots$]