Generate a topic word for the given sentence. A topic word is usually the name of a person, place, animal, concept or object the sentence is focusing on.

[EX Q]: the vektor r4 is a south african assault rifle.
[EX A]: vektor r4

[EX Q]: mohamed allalou (born september 28, 1973) is an algerian boxer.
[EX A]: mohamed allalou

[EX Q]: control theory is an interdisciplinary branch of engineering and mathematics.
[EX A]:
control theory