## Announcements ##
-The seminar meets on Mondays, starting September 13, from 4-6.
-We'll be meeting in the Linguistics building at 10 Washington Place on the first floor (room 104).
+* The seminar meets on Mondays from 4-6, in
+the Linguistics building at 10 Washington Place, in room 104 (back of the first floor).
+
+* One student session will be held every Wednesday from 3-4. The other will
+be arranged to fit the schedule of those who'd like to attend but can't
+make the Wednesday time. (We first proposed Tuesdays from 11-12, but this
+time turns out not to be so helpful.) If you're one of the students who
+wants to meet for Q&A at some other time in the week, let us know.
+
+ You should see the student sessions as opportunities to clear up lingering
+issues from material we've discussed, and help get a better footing for what
+we'll be doing the next week. It would be smart to make a serious start on that
+week's homework, for instance, before the session.
+
+* There is now a [[lambda evaluator]] you can use in your browser (no need to
+install any software). It can help you check whether your answer to some of the
+homework questions works correctly.
+
+ There is also now a [library](/lambda_library) of lambda-calculus
+arithmetical and list operations, some relatively advanced.
+
+ An evaluator with the definitions used for homework 3
+preloaded is available at [[assignment 3 evaluator]].
+
+* Henceforth, unless we say otherwise, every homework will be "due" by
+Sunday morning after the Monday seminar in which we refer to it.
+(Usually we'll post the assignment shortly before the seminar, but don't
+rely on this.) However, for every assignment there will be a "grace
+period" of one further week for you to continue working on it if you
+have trouble and aren't able to complete the assignment to your
+satisfaction by the due date. You shouldn't hesitate to talk to us---or
+each other!---about the assignments when you do have trouble. We don't
+mind so much if you come across answers to the assignment when browsing
+the web, or the Little Schemer book, or anywhere. So long as you can
+reason yourself through the solutions and experience for yourself the
+insights they embody.
+
+ We reserve the privilege to ruthlessly require you to
+explain your solutions in conversations at any point, in section or in
+class.
+
+ You should always *aim* to complete the assignments by the "due" date,
+as this will fit best with the progress of the seminar. Let's take
+assignment 3 to be "due" on Sunday Oct 3 (the date of this
+announcement), but as we announced last week in seminar, you can take up
+until this coming Sunday to complete it. If you need to. Try to complete
+it, and get assistance completing it if you need it, sooner.
+
+* We'll shortly be posting another assignment, assignment 4, which will be
+"due" on the Sunday before our next seminar. That is, on Sunday Oct 17.
+(There's no seminar on Monday Oct 11.)
+
+ The assignments will tend to be quite challenging. Again, you should by
+all means talk amongst yourselves, and to us, about strategies and
+questions that come up when working through them.
+
+ We will not always be able to predict accurately which problems are
+easy and which are hard. If we misjudge, and choose a problem that is
+too hard for you to complete to your own satisfaction, it is still
+very much worthwhile (and very much appreciated) if you would explain
+what is difficult, what you tried, why what you tried didn't work, and
+what you think you need in order to solve the problem.
-We've sent around an email to those who left their email addresses on the roster we passed around. But it's clear that the roster didn't make its way to everyone. So if you didn't receive our email this evening, please email <mailto:jim.pryor@nyu.edu> with your email address, and if you're a student, say whether you expect to audit or take the class for credit.
+<!--
+ To play around with a **typed lambda calculus**, which we'll look at later
+ in the course, have a look at the [Penn Lambda Calculator](http://www.ling.upenn.edu/lambda/).
+ This requires installing Java, but provides a number of tools for evaluating
+ lambda expressions and other linguistic forms. (Mac users will most likely
+ already have Java installed.)
+-->
+
+
+## Lecture Notes and Assignments ##
+
+(13 Sept) Lecture notes for [[Week1]]; [[Assignment1]].
+
+> Topics: [[Applications]], including [[Damn]]; Basics of Lambda Calculus; Comparing Different Languages
+
+(20 Sept) Lecture notes for [[Week2]]; [[Assignment2]].
+
+> Topics: Reduction and Convertibility; Combinators; Evaluation Strategies and Normalization; Decidability; [[Lists and Numbers]]
+
+(27 Sept) Lecture notes for [[Week3]]; [[Assignment3]];
+an evaluator with the definitions used for homework 3
+preloaded is available at [[assignment 3 evaluator]].
+
+> Topics: [[Evaluation Order]]; Recursion with Fixed Point Combinators
+
+(4 Oct) Lecture notes for [[Week4]]; [[Assignment4]].
+
+> Topics: More on Fixed Points; Sets; Aborting List Traversals; [[Implementing Trees]]
+
+
+(18 Oct) Lecture notes for Week 5
+
+> Topics: Types, Polymorphism
-All students are invited to help us schedule, and then participate in, a regular student session in addition to the Monday seminar meetings. If you didn't receive our email about this, go to
-<http://www.doodle.com/e8eci7cr9ib8t7t3> as soon as you can and please tell us when you're available.
+[[Upcoming topics]]
-## Assignments ##
+[Advanced Lambda Calculus Topics](/advanced_lambda)
-[[Assignment1]]
+
+##[[Offsite Reading]]##
+
+There's lots of links here already to tutorials and encyclopedia entries about many of the notions we'll be dealing with.
-## Overview ##
+
+## Course Overview ##
The goal of this seminar is to introduce concepts and techniques from
theoretical computer science and show how they can provide insight
what that means during the course.
* **Scheme** is one of two major dialects of *Lisp*, which is a large family
-of programming languages. The other dialect is called "Common Lisp." Scheme
+of programming languages. Scheme
is the more clean and minimalistic dialect, and is what's mostly used in
academic circles.
Scheme itself has umpteen different "implementations", which share most of
Racket stands to Scheme in something like the relation Firefox stands to HTML.
* **Caml** is one of two major dialects of *ML*, which is another large
-family of programming languages. The other dialect is called "SML" and has
-several implementations. But Caml has only one active implementation,
+family of programming languages. Caml has only one active implementation,
OCaml, developed by the INRIA academic group in France.
* Those of you with some programming background may have encountered a third
[[How to get the programming languages running on your computer]]
-[[Using the programming languages]]
-
[[Family tree of functional programming languages]]
+
## Recommended Books ##
+It's not necessary to purchase these for the class. But they are good ways to get a more thorough and solid understanding of some of the more basic conceptual tools we'll be using.
+
* *An Introduction to Lambda Calculi for Computer Scientists*, by Chris
Hankin, currently $17 on
[Amazon](http://www.amazon.com/Introduction-Lambda-Calculi-Computer-Scientists/dp/0954300653).
* *The Little MLer*, by Matthias Felleisen and Daniel P. Friedman, currently $27
on [Amazon](http://www.amazon.com/Little-MLer-Matthias-Felleisen/dp/026256114X).
This covers some of the same introductory ground as The Little Schemer, but
-this time in ML. The dialect of ML used is SML, not OCaml, but there are only
+this time in ML. It uses another dialect of ML (called SML), instead of OCaml, but there are only
superficial syntactic differences between these languages. [Here's a translation
manual between them](http://www.mpi-sws.org/~rossberg/sml-vs-ocaml.html).
-##[[Schedule of Topics]]##
-
-##[[Lecture Notes]]##
-
-##[[Offsite Reading]]##
-
-There's lots of links here already to tutorials and encyclopedia entries about many of the notions we'll be dealing with.
----
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