This lecture covers the proof of the convergence rate theorem, focusing on the correction of a missing factor sqrt{pi_j} at the end of the proof of the lemma, as reflected in the slides. The slides detail the step-by-step proof of the theorem, highlighting the importance of sqrt{pi_j} in the convergence rate. The instructor explains the significance of this correction in ensuring the accuracy of the theorem's proof and its implications in the context of the lecture.