Applied mathematics in theoretical physics and classical mechanics

Applied mathematics have a huge function in theoretical physics. Classical mechanics, quantum mechanics are built their base on mathematics and applied mathematics. Different theories and rules are proved mathematically by the blessing of applied mathematics. The different popular topics in physics are defiend mathematically. Without mathematical prove these theories are out of date. Quantum mechanics is an important part of physics and applied physics. Quantum mechanics also an application of applied mathematics. Cosmology, plasma science, black bole, relativity, time, space, etc are the popular topics of applied mathematics.