12-06. Discrete-time Markov chains - Recurrence and transience: 1D random walk.

Whole-channel inclusion: The probability channel [Professor Lanchier] is an honest teaching channel (title sample + 3 transcripts read: All three samples lack transcripts, but titles/descriptions indicate structured probability theory lectures consistent with the channel's established educational pattern.); this title passed a strict title check (sonnet) after a labelling pass.