Being a third-party compilation, there are occasional mismatched symbols (e.g., using ⊂ for subset vs. proper subset inconsistently) and one glaring error in an induction proof (n=1 base case is fine, but the inductive step misuses the hypothesis). Fortunately, the errata sheet (included) fixes it.
Are you planning to take this course as a , or are you looking for online self-study resources to learn proof-writing? 18.0x - MIT Mathematics Being a third-party compilation
Week 14:
Direct proofs, contrapositives, and converse statements. there are occasional mismatched symbols (e.g.