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.

vehari district is a district in the punjab province of pakistan.
vehari district

a mathematician's apology is a book about mathematics which was written in 1940.
a mathematician's apology

flurbereinigung (pronounce: flooer-be-rye-nee-gung) is a word used in germany to refer to the rearranging of fields in agriculture.

flurbereinigung