I've run through some playlists on this channel and I am quite familiar with those things thanks to my dad's garage filled up with soviet math books :) My concern is not about my prep for master but about written proof of my math competence for PhD adcom, I mean courses like RA,DE, calc-123 courses on the undergrad transcript record . So, I am wondering how can I do that: to take GRE math, or some online courses like MIT's micromasters, harvard extension or take non-credit courses from another university? I mean, it is not as if I'm gonna write in my PhD SOP "Hey adcom guy, I haven't been taught math at university but I can explain what is isolated point and prove bolzano/weierstrass theorem to you"
Yeah, you are right. It is not about pure math, it is likely more applied. Here is some courses of this mater: Topics in algebra and Number theory, Topics in mathematical analysis; Mathematical modelling; Econometrics; Computational complexity theory; Discrete function theory; Calculus of variations; Computational optimization; Asymptotic methods in analysis; Intelligent system theory; Imitation and modelling; Automata theory