He is responsible for a great body of work in group theory.
His work has been in the field of group theory.
He is known for his work in the area of group theory.
The study of this category is known as group theory.
His classic book on group theory was well received when it came out and is still useful today.
What about the development of group theory from Galois' time up to 1900?
These groups play an important role in geometric group theory.
Using basic group theory, the reason these solutions are not incredibly difficult to find will become clear.
It was held up as a triumph of group theory in physics.
It also provided an important outlet for real analysis and the new group theory.