I want to learn math for machine learning, and I want to start with informal set theory.
I was reading 'naive set theory' (1960) by halmos, and it didn't seem to contain modern set notations.
If anyone knows a good material for learning informal set theory, please leave a comment.
That being said, I do not mind some rigor as long as it helps me with statistics, calculus, and other math fields used in machine learning.