How Harmonic Functions Relate to Holomorphic Functions

We explore how real harmonic functions are related to complex holomorphic/analytic functions in a few ways. Notably holomorphic functions have harmonic real and imaginary parts. Further, we prove that the level curves of the real and imaginary parts are typically orthogonal to each other.

[khaledchbichib]

I think that your note at 8:16
isn t true. Just take U and V harmonic but not verify C.R. then U+iV not holomorphic