{HEAD ~ Concurrent programs} with {TAIL ~ many replicated threads}, e.g., running the same piece of code, occur in many important applications 
with
{ HEAD ~ Concurrent programs } with { TAIL ~ many replicated threads } , e.g. , running the same piece of code , occur in many important applications
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH