He is an expert in paleobotany.

He is an expert in paleozoology and has a deep knowledge about the ecology of dinosaurs.

Paleoecology is a field of study that investigates the relationship between past organisms and their environment.

Paleogeography is a study that researches the past geographical conditions of the Earth.

He is an expert in orthoepy, teaching pronunciation.

I am learning the basic concepts of differential geometry.

Computational geometry is an important field of computer science.

Projective geometry is a branch of mathematics that studies geometric objects such as points, lines, and planes and their relationships.

Riemannian geometry is a field of mathematics that studies geometric objects such as curves and surfaces.

He is an expert in applied physics.