Improvement (?) on description about the concurrency project.

research/concurrency.md

@@ -8,7 +8,7 @@ Concurrent programs and libraries are ubiquitous in today's world of multi-core
 and the need for reasoning about concurrent programs and verifying their correctness grows 
 increasingly more important. These research problems are still considered difficult for a variety of reasons,
 such as the fact that we need to consider and reach conclusions about a shared state 
-affected by multiple threads, or [another reason].
+affected by multiple threads, or that we require effective abstractions for describing the complex behaviour created by multiple threads.
 
 Our research agenda is to develop formal reasoning methods about concurrency with a focus on concurrent program logics.
 Recently, various logics based on separation logic were introduced with the aim of verifying functional correctness of fine-grained concurrent programs.