CS103 Archive

This page contains archived versions of the Stanford CS103 (Mathematical Foundations of Computing) webpage in the quarters I've taught it. All internal links should be valid, though external links may no longer be functional.

2015-2016 Academic Year
Winter 2016

This offering of CS103 - which, I think, was the most polished the class has been to date - was essentially the Fall 2015 version with a ton of cleanup and two whole lectures (!!) of content removed to accommodate the Winter schedule. With the lessons learned from Fall 2015, I managed to significantly tighten up the presentation of TMs (scaling down the intellectual burden involved with subroutines, for example) and come up with a much better lecture on complete induction (thanks, trees!). I've also made a ton of notes to myself with areas for future improvement, mostly with regards to moving motivations earlier into lecture and trying to take some of the more theory-heavy topics and replace them with more practical applications.

This quarter, I introduced the Guide to Self-Reference and Guide to the Lava Diagram, two animated slide decks walking through the intuition for two of the trickiest topics from the quarter. They were very well-received and I'm extremely proud of how well they turned out. I think they really worked - people did a lot better on the final exam questions on computability than they've historically done in the past. I'm hoping to expand these guides throughout the quarter and rework some of the supporting handouts from throughout the quarter to use this new format.

There's still a lot of work to be done to get this class into a good working order. I need to figure out a better way to design exams that communicate our expectations. I need to find some way to integrate more of the topics from the discrete math section into the computability/complexity topics. I also need to find a way to cut even more material, since we're still totally overloaded with material. That said, this version of the class got some of the highest reviews CS103 has ever received, so there's still a lot to be really happy about!

Fall 2015

This offering of CS103 started with a pretty serious overhaul of the first half of the class. I moved first-order logic to the second week and gave an entire problem set pretty much devoted to first-order and propositional logic. Using that as a starting point, I increased the treatment of discrete mathematics and spent a lot more time in class going over how to use first-order logic as a tool for reasoning about proofs. I added in a new problem set about graphs, and pushed induction to the end of the section on discrete structures rather than the beginning. The net result seems to be that people got a much better treatment of discrete math and had much better outcomes with proofwriting and formal definitions.

To fit all this in, I used the two extra lectures that come with a fall quarter class. I also removed nondeterministic TMs from the CS103 lineup, which freed up about half a lecture from the section on Turing machines and another half lecture from the portion on P and NP. I also lowered my expectations about student outcomes with P versus NP, since they'll get a more in-depth treatment of the subject in CS161 (and CS154, if they choose to take it).

I also for the first time introduced a series of challenge problems throughout the quarter for students interested in more of a challenge. I'm really happy with the first set of challenge problems (which lead up to a proof about the chromatic number of the rational plane) and pretty happy with the other two. I hope to keep using them in the future.

As promised, I also introduced a ton of new handouts. It's unclear how effective they were, though I did find an unusual trend in the grades: freshman in CS103 this quarter did substantially better than every other group. I'm wondering if this is because the freshmen were actually going through all the materials, or whether this is due to other effects.

The overhaul required a ton of effort, and I'm really hoping that next quarter will be more relaxing. I know that I need to tune up my presentation of TM subroutines (which, right now, are terrifying), my coverage of complete induction (I still have never really gotten that one to work right), and my coverage of P versus NP (which right now, I think, is a bit too high level). I also will need to figure out how to cut a lecture for winter quarter (one bonus lecture on Eulerian graphs is easy to eliminate). I've taken tons of notes on my materials for next time, so hopefully I'm closing in on a stable, final version of this class!

2014-2015 Academic Year
Spring 2015

I was very pleased with how this iteration of CS103 worked out. I ended up continuing to use the recursion theorem as a primary mechanism for showing undecidability and unrecognizability, but significantly overhauled the presentation to focus more on actual source code than on high-level descriptions. This cleaned up much of the presentation and made it much easier for students to see how these constructions worked. I also reordered the treatment of verifiers and NTMs to put verifiers earlier, then heavily push verifiers as a mechanism for understanding RE. This made a lot of the proofs easier to understand and replaced complicated nuances of recognizers for simpler (though still tough) notions of verification.

This quarter also marked a return to an older model where I covered first-order logic prior to discussing graphs, binary relations, and functions, which I believe helped out quite a bit. There is still a lot more work to be done integrating first-order logic into the discrete structures porition of the course - specifically, I need to do a much better job talking about how to write proofs that call back to formal definitions - but I think it made it easier to define complex concepts more precisely.

Finally, this quarter marked the first iteration of CS103A, an add-on course providing extra review and problem-solving practice. That class went pretty well for a first offering, and I'm hoping to tune it a lot more precisely in the future.

Next time I teach this course, I'm going to improve in a few specific areas. First, I need to do a better job teaching students how to manipulate first-order definitions and how to use them to guide the basic structure of mathematical proofs. That's going to be a bit tough, especially given that we're already packed to the gills with material. Second, I need to update my presentation of P and NP, probably by cutting out the NTM intuition for NP and focusing more on reducibility and verification. Finally, I need to provide more support materials along the way, either by fleshing out the course reader, building a more supplementary handouts, or some combinatino of both. That said, this was, in my opinion, easily the best offering of CS103 to date, and I'm quite happy with how the class looks now.

Fall 2014

This was my sixth offering of CS103. I ended up making a lot of changes since the prior offering. Students were allowed to work on problem sets in pairs and triples, which helped students get more practice writing proofs and significantly cut down on the TA grading load. I started offering in-person practice midterms, leading to much better exam performances overall. I also changed the discussion of computability quite significantly by focusing on the recursion theorem as a method for showing impossibility results and exploring equivalent definitions of the class RE through verifiers. I think that I'm on to something with this setup but that it needs a bit more tuning, so we'll see how it goes next time around. (Oh, and this class broke the CS103 size record by about 80 students!)

2013-2014 Academic Year
Fall 2013

This fifth offering of CS103 broke the size record by quite a large margin (333 students!). I made a lot of changes to the course that really seemed to pay off. I updated the treatment of discrete math to stress discrete structures more than in past quarters and, accordingly, revised some of the problem sets. I also replaced the pumping lemma with the Myhill-Nerode theorem, which made for a much more intuitive presentation of nonregular languages and led to some much cooler problem set questions. I revised all the discussion problems to be more relevant, gave out more practice problems, and dedicated a few minutes of lecture time each day to answering questions students asked via Google Moderator. CS103 got its highest evaluations ever and was one of the highest-rated courses in the entire School of Engineering, and I'm extremely happy with how it turned out. That said, I've got a lot of ideas I want to test out next time, so I'm looking forward to the next time I get to teach it!

  • Total students enrolled: 333
  • Lecture Topics:
    • Week 1: Set Theory, Cantor's Theorem, Proof Techniques
    • Week 2: Induction, Graphs
    • Week 3: Graphs, Relations, Functions
    • Week 4: Cardinality, Logic
    • Week 5: Logic, DFAs, NFAs
    • Week 6: Regular Expressions, Myhill-Nerode Theorem, CFGs
    • Week 7: Turing Machines, The Church-Turing Thesis
    • Week 8: Unrecognizablility, Undecidability, co-Recognizability
    • Week 9: Mapping Reductions, P, NP
    • Week 10: P vs. NP, NP-Completeness, The Big Picture
2012-2013 Academic Year
Winter 2012-2013

This fourth offering of CS103 was the largest offering I'd taught so far (with 265 students!) I was extremely happy with how the material worked out this time - the coverage of Turing machines was a lot more focused, and more generally the intuitions seemed to shine through marvelously. We also added in a new Regular Expression design tool (thanks, Remington!) that made it possible to test regular expressions in more depth. I am very much looking forward to the next iteration of CS103, when I think that I'll finally have all the bugs ironed out!

  • Total students enrolled: 265
  • Lecture Topics:
    • Week 1: Set Theory, Cantor's Theorem, Proof Techniques
    • Week 2: Induction, Graphs, Relations
    • Week 3: Functions, Cardinality, Diagonalization, the Pigeonhole Principle
    • Week 4: Propositional Logic, First-Order Logic, SAT Solving
    • Week 5: DFAs, NFAs, and Regular Expressions
    • Week 6: The Pumping Lemma, CFGs, PDAs
    • Week 7: Turing Machines, The Church-Turing Thesis
    • Week 8: Unrecognizablility, Undecidability, co-Recognizability
    • Week 9: Mapping Reductions, P, NP
    • Week 10: P vs. NP, NP-Completeness, The Big Picture
Fall 2012

This was the third time I taught CS103. This quarter marked the introduction of the Theorem and Defintion reference, a set of course notes for the first few weeks, and an automatic grade reporting tool. I'm very happy with how the quarter turned out, and I'm really psyched to build off of it for the upcoming Winter quarter!

  • Total students enrolled: 185
  • Lecture Topics:
    • Week 1: Set Theory, Cantor's Theorem, Proof Techniques
    • Week 2: Induction, Graphs, Equivalence Relations
    • Week 3: Order Relations, Functions, Cardinality, the Pigeonhole Principle
    • Week 4: Propositional Logic, First-Order Logic, SAT Solving
    • Week 5: DFAs and NFAs
    • Week 6: Regular Expressions, The Pumping Lemma, CFGs, PDAs
    • Week 7: Turing Machines, Programming Turing Machines, R and RE Languages
    • Week 8: Unsolvable Problems, Mapping Reductions, co-RE
    • Week 9: P, NP, NP-Completeness
    • Week 10: NP-Completeness, Approximation Algorithms, Cryptography, The Big Picture
2011-2012 Academic Year
Spring 2012

The second offering of CS103 was a lot more polished than the first run. I wrote a set of course notes for the first week of the course, and significantly tightened up the treatment of proof techniques and reductions. I am very happy with how this offering of the class turned out, and I'm very excited to see how well it will go when I teach it this Fall!

  • Total students enrolled: 181
  • Lecture Topics:
    • Week 1: Set Theory, Cantor's Theorem, Direct Proofs, Indirect Proofs
    • Week 2: Induction, Graphs, Relations
    • Week 3: Functions, the Pigeonhole Principle, Propositional Logic
    • Week 4: First-Order Logic, SAT Solving, DFAs
    • Week 5: NFAs, Regular Expressions, the Pumping Lemma
    • Week 6: Context-Free Grammars, Pushdown Automata, Turing Machines
    • Week 7: The Church-Turing Thesis, Universal TMs, Unsolvable Problems
    • Week 8: Reductions, P
    • Week 9: NP, NP-Completeness
    • Week 10: Approximation Algorithms, The Big Picture
Fall 2011

This was a quarter of firsts - my first quarter as a full-time lecturer at Stanford, my first time teaching CS103, and the first time teaching a class with over 200 students. I had a great time teaching and while the class had a few rough edges (as expected for a first iteration), I'm really psyched to teach it again.

  • Total students enrolled: 213
  • Lecture Topics:
    • Week 1: Set Theory, Cantor's Theorem, Graphs, Relations, Direct Proofs
    • Week 2: Proofs by Contradiction and Contrapositive, Induction
    • Week 3: Double Induction, Strong Induction, Propositional Logic
    • Week 4: First-Order Logic, Functions, the Pigeonhole Principle, Trees
    • Week 5: DFAs and NFAs
    • Week 6: NFAs, Regular Expressions, the Pumping Lemma
    • Week 7: Context-Free Grammars, Pushdown Automata, the Pumping Lemma for CFLs
    • Week 8: Turing Machines, the Church-Turing Thesis, the Halting Problem, Properties of RE Languages
    • Week 9: Reductions, Rice's Theorem, P, NP
    • Week 10: NP-Completeness, Approximation Algorithms