allow dReal to accept partially specified ODEs. needed for distributed systems. 

syntax: 
partial integral terms: 
(pintegral ... [holder_1 holder_2 ...])
Here, holder list replaces the original single flow. To specify any holder dynamically, write:
(connect holder_i flow_j)
where flow_j was declared previously, which doesn't need to mention all variables. (No need to declare holders)

Make sure that a complete set of ODEs are specified after instantiating all holders.