Complex sentence: There are a number of "agents" and an equal number of "tasks", we want to search a way to assign each agent exactly one task such that the total "cost" of the assignment is minimized.
Split into simpler sentences: There are a number of "agents" and a number of "tasks". It is required to perform all tasks by assigning exactly one agent to each task in such a way that the "total cost" of the assignment is minimized.