MDPs I: Putting Uncertainty into State Transitions | Stanford CS221 Lecture 7
Lecture 7 of Stanford CS221 Autumn 2025 follows the official material on MDPs I: Putting Uncertainty into State Transitions and makes its assumptions and limits explicit.
Lecture 7 of Stanford CS221 Autumn 2025 follows the official material on MDPs I: Putting Uncertainty into State Transitions and makes its assumptions and limits explicit.
Lecture 8 of Stanford CS221 Autumn 2025 follows the official material on MDPs II: Learning Q-Values Without a Transition Model and makes its assumptions and limits explicit.
Lecture 9 moves from tabular RL to function approximation, derives REINFORCE with the log-derivative identity, and connects the derivation to the executable PyTorch implementation.
Lecture 10 extends single-agent search into adversarial game trees: expectimax averages chance outcomes, minimax takes the opponent's worst case, and alpha-beta removes irrelevant branches without changing the answer.
Lecture 11 first learns game values from experience with temporal-difference updates, then moves from sequential play to simultaneous games described by mixed strategies, minimax guarantees, and Nash equilibria.
Lecture 12 builds a joint distribution from random variables and factors, then uses Bayesian-network factorization to express conditional independence and make conditioning and marginalization executable.
Lecture 13 replaces costly exact inference with Gibbs sampling: resample one variable at a time from a conditional determined by its Markov blanket, then approximate query probabilities with sample frequencies.
Lecture 14 moves from maximum-likelihood counts and Laplace smoothing with complete data to EM, which alternates posterior responsibilities for latent variables with parameter updates.
Lecture 15 separates propositional syntax from semantics: model checking defines entailment through satisfying assignments, SAT finds witnesses, and inference rules must be judged for both soundness and completeness.
Lecture 16 compresses knowledge across objects with predicates, quantifiers, and functions, then derives conclusions through substitution, unification, and definite-clause forward inference while exposing termination and completeness limits.
Lecture 17 defines a language model as a chain-rule factorization of sequence probability, compares n-gram and neural conditional models, and shows how sampling, temperature, and evaluation shape generation.
Lecture 18 classifies AI's social effects as benefits, misuse, accidents, and structural harms, then connects fairness audits, research ethics, copyright, and platform terms to accountable institutional choices.
Lecture 19 uses the Economics of AI deck to connect compute, data, distribution, and organizational complements to GDP, labor, and ideas-driven growth.
Lecture 20 is Percy Liang's fireside chat on career and research, CS221 and Stanford, and AI's future, with every attribution tied to the official video and editorial synthesis kept separate from auto-caption uncertainty.
A slide-grounded reconstruction of Fall 2025 Lecture 1, covering Course map and tools, A common language for graph data, Hand-designed features and representation learning while documenting the classroom material unavailable to self-learners.
A slide-grounded reconstruction of Fall 2025 Lecture 2, covering Encoder-decoder view, Similarity and the objective, Random walks while documenting the classroom material unavailable to self-learners.
A slide-grounded reconstruction of Fall 2025 Lecture 3, covering From fixed embeddings to deep encoders, The message-passing framework, Aggregation and update while documenting the classroom material unavailable to self-learners.
A slide-grounded reconstruction of Fall 2025 Lecture 4, covering The GNN design space, Message, aggregation, and update, GraphSAGE while documenting the classroom material unavailable to self-learners.
A slide-grounded reconstruction of Fall 2025 Lecture 5, covering Graph-data augmentation, Feature and structural augmentation, Supervision and loss while documenting the classroom material unavailable to self-learners.
A Fall 2025 slide-grounded reconstruction of Lecture 6, covering What distinguishability means, The Weisfeiler–Lehman test, An upper bound for message passing while documenting unavailable classroom material.