I hope my question is in the scope of MSE.
I want to study 1- Fourier Analysis, 2- Functional Analysis and 3- Operator Theory, all from scratch.
Which one I need to study first? second? and third? Or, can I study them parallel?
PS I know that I need advanced Real Analysis (for inclusion of Measure Theory). But I don't know what other primary mathematics is required for each of the mentioned three subject.
Edit - I have finished my BSc-maths and I want to learn all the three mentioned subject in graduate (MSc-maths(pure)) level.