Smooth space-time integration by parts #
Directional integration by parts for a smooth field and a compactly supported test on the raw product of space and time, expressed using factor derivatives.
The time factor derivative is the joint derivative in the time direction.
A directional derivative of a smooth scalar function is smooth.
Integration by parts in an arbitrary space-time direction.
Space-time integration by parts for a spatial factor derivative.
Space-time integration by parts for the time factor derivative.
Smoothness of a spatial factor derivative.
A spatial derivative has no larger support than its smooth input.
A time derivative has no larger support than its smooth input.
A smooth field times a compactly supported test is integrable.
Products with spatial test derivatives are integrable.
Products with time test derivatives are integrable.
Product rule for spatial factor derivatives.
Product rule for time factor derivatives.
Two spatial integrations by parts against a compactly supported test.