Definition
Euler's homogeneous function theorem
Let f(x, y) to be a homogeneous function of order / degree n, then we have:
Application in economics
For a production function f(L, K) that is constant return to scale, we know it is also homogeneous to degree 1. Thus apply Euler's theorem, we have:
Note
https://mathworld.wolfram.com/EulersHomogeneousFunctionTheorem.html