［中文］历史 History:
Sir Atiyah Proof on 2018 September : (5 Pages PDF download here)
https://drive.google.com/file/d/17NBICP6OcUSucrXKNWvzLmrQpfUrEKuY/view
Bigger Lecture Notes video (at 34 mins, inspired in Singapore)
Analytic function: preserve angle after transformation
Mathtuition88 