A good way to start is learn set theory (start of with naive set theory Dover books are cheap: http://store.doverpublications.com/0486814874.html http://store.d

A good way to start is learn set theory (start of with naive set theory Dover books are cheap: http://store.doverpublications.com/0486814874.html http://store.doverpublications.com/0486814874.html) And some introductory mathematical logic. From this you can immediately move to Analysis on the real line (up to Reimann integrals) Linear Algebra is also something you can start (Kenneth Hoffman and Ray Kunze https://www.amazon.com/Linear-Algebra-Kunze-Hoffman/dp/9332550077 https://www.amazon.com/Linear-Algebra-Kunze-Hoffman/dp/93325...) Once you are comfortable with Riemann Integrals, you can start attacking Complex Variables (John Conway has excellent springer texts: Functions of One Complex Variable Vol 1 and 2) Some texts you should look at after you understand basic set theory: Analysis: 1. [Michael_Spivak]_Calculus - good book for introduction to real analysis 2. [johnsonbaugh,pfaffenberger]_Foundations_of_Mathematical_Analysis - Dover publications 3. [Vladimir_A._Zorich]_Mathematical_Analysis_I - well written but less known. Recommend checking it out. 4. [Gerald_B._Folland]_Real_Analysis_Modern_techniques_and_their_applications - My top pick, but a tough read. 5. [Rudin_Walter]_Principles_of_Mathematical_Analysis - classic book Linear Algebra: 1. [David_Lay]_Linear_Algebra_and_Its_Applications - 2. [Friedberg,Insel,Spence]_Linear_algebra - Undergraduate level text 3. [Hoffman,Kunze]_Linear_Algebra_2nd_edition - Graduate level text. My top pick. 4. [Gilbert_Strang]_Introduction_to_Linear_Algebra - Undergraduate level linear algebra. Same guy has MIT OCW lectures. 5. [Peter_D._Lax]_Linear_Algebra_and_Its_Applications Complex Variables/Complex Analysis: 1. [John_Conway]_Functions_of_One_Complex_Variable_I - My top pick 2. [Lars_Ahlfors]_Complex_Analysis_(Third_Edition) - Classic. Not a big fan though.