Announcements

• I've listed the final exam grades and final grades for people whose ID#s I have HERE.

• HOW DO I KNOW HOW MANY POINTS I MISSED ON PSXII?

  I'd assumed it would be obvious to people that they wouldn't find out the answer to this question before the exercises for make-up points were due. But my email account has been flooded with people asking this question, so I figure it's easiest just to tell you how to work it out for yourself. Here's how we're grading PSXII:

  14.3 (5 points): 1 point for each correct answer (no further breakdown of partial credit).
  14.4 (7 points): 1 point for each correct answer (no further breakdown of partial credit).
  14.5 (6 points): 3 points for each correct translation (no further breakdown of partial credit).
  14.11 (5 points): (All or nothing)
  14.13 (5 points): (All or nothing)
  14.14 (3 points): (All or nothing)
  14.28 (5 points): 1 point for each correct answer (no further breakdown of partial credit).
  

• REVIEW SESSION

  Bob and Allyson will hold a review session on Tuesday, May 6^th, from 1PM-2:30 in room 142 Goldwin Smith Hall. Please come prepared with questions.

• COURSE EVALUATIONS

  If you missed lecture on the day that course evaluations were handed out, and would still like to fill one out, you may pick one up from (and return it to) one of the office staff in the philosophy department at 218 Goldwin Smith Hall.

• WHEN IS THE FINAL?

  According to CU Info, the final exam is scheduled for May 9^th at 9AM in Kaufmann Auditorium.

• WHAT'S ON THE FINAL?

  For the final exam you are responsible for all reading assigned from the assignments page (not counting chapter 15, though there may be an extra credit from chapter 15 on the final), as well as all lecture material. Soundness and completeness are discussed in 8.3 and 13.4. Modelling properties of relations is discussed a bit in 15.5, although in class we discussed this in relation to formal proofs, while in ch. 15, this is discussed in relation to set theory.

• WHAT DO WE GET FOR HAVING DONE THE EXTRA CREDIT PROBLEMS? (Not to be confused with the make-up points.)

  Here's how grading for extra credit works. The first EC problem was worth 3 points. The two remeaining EC problems are worth 10 points each. If you already have an A average, then enough EC points can bump you up to an A+. (You cannot get an A+ unless you get EC points.)

• HOW MANY POINTS HAVE I MISSED ON HOMEWORKS?

  You can now see how many points you've missed on homeworks through Problem Set XI here (access restricted to Cornell).

  If you do not see your ID number here, it means either that I don't know your ID number, or that you told me you didn't need/want this information to be posted. Let me know by email what your ID# is (with subject heading: PHIL 231 ID#) if you'd like to see your information posted here and it isn't already.

• WHEN SHOULD I TURN IN MY EXERCISES FOR MAKE-UP POINTS?

  Exercises for make-up points are to be turned in on Monday, May 5^th. Not before. Not after. (In a previous announcement, I'd erroneously written Monday, May 4^th.) No exercises for make-up points are to be turned in either before or after the scheduled day.

• MAKE-UP POINTS.

  You will be able to earn make-up points (at a a rate of two points per problem done) for points missed on homeworks in accordance with the following instructions. If you do not adhere to all instructions, you will not get any credit for your make-up work.

  1. All make-up problems must be submitted to us via the Grade Grinder on Monday, May 5^th. Not after. Not before.
  2. Exercises must be from Part II of the textbook or later.
  3. Exercises submitted cannot be those assigned as regular homework exercises.
  4. You may only make up for points missed on problem sets, not on exams (or extra credits!).
     (In other words, if you score perfectly on all the homeworks (whether or not you did any extra credit), then you are not elligible for make-up points, no matter how poorly you do on the exams.)
  5. If you submit more problems than you're elligible to receive credit for, then you will not get any make-up credit at all.
     (Going over by an amount less than two is okay. So, for example, if you've missed three points on all the homeworks put together, then you're elligible for three make-up points, which you'd get by submitting two problems.)
  6. Electronic exercises only.
     (Exercises with both a written component and an electronic component are not allowed. Any exercise whose full submitted solution involves only an electronic component is allowed, even if part of the problem is to figure out whether the solution requires an electronic or a written answer.)
  7. Exercises must be submitted all together; or, if there's a limit to how many can be submitted together, then they must be submitted in as few emails as the grade grinder and submit program will allow.
     (I don't actually know whether Submit puts a limit on how many files may be submitted together. If someone finds out the answer to this question, could they let me know?)
  8. You can only get credit for an exercise solution with no mistakes on it.
  9. No collaboration of any kind with other people.
     If we get any indication whatsoever that you are sharing computer files with anyone else, we will not give you any credit for your make-up work.

• You might like to check out this web site: November's Great Moments in Logic, a page from the website of Greg Restall (a philosophy professor at Melbourne) introducing a logician a day (with pictures) for each day in November (2001).

• WHAT ABOUT THE ROOT-TWO PROOF?

  You now know enough to be able to do the extra credit problem mentioned at the outset of the semester: converting my "informal" proof that sqrt(2) is irrational into a formal prof in the Fitch natural deduction system. You should type up the proof in the Fitch program, print that out, and hand it into your section leader (please do click "verify proof" before saving to make our life easier!) or email it to them. It is due by Slope Day.

  Further instructions, hints and help (list not yet complete, but complete enough for you to get started on this now):

  • You may not use TAUT CON (or FO CON or ANA CON), except to justify an instance of excluded middle.

  • All the premises of your proof should be either definitions of mathematical predicates or function symbols, or statements of arithmetical/number-theoretic facts. Your premises should all be *general* (not inolve any names of particular numbers except the number 2 in your definition of what it is for a number to be even).

    Note that you to not have to give a definition of every mathematical predicate that you use; only need to give definitions where appeal to the definition is involved in your proof. For example, you will probably need to have as a premise a definition of what it is for a number to be rational, and a definition of what it is for a number to be even, such as the following (Fitch has a symbol for multiplication, so you may use that where I use 'prod'):

    Ax(Even(x) <-> (Integer(x) ^ Ey x = prod(2,y)))

    You will probably not, however, have need to define the predicate 'Integer'. Note that in FOL, definitions will typically have the form of a universally quantified biconditional.

  • You must not have FO validities as premises. For example, the following is FO Valid, and thus must not occur as a premise:

    AxAy(x=y -> sqr(x)=sqr(y))

    (Here I use 'sqr(x)' to denote the the square of x.)

  • Note that the pair of exercises 13.34-13.35 from PSXI is instructive for formalizing the root-two proof. The validity of 13.34 depends on 'SameCol' being a transitive relation. Fitch is programmed to know about facts concerning the special subject matter of blocks placed on grids, so that you can use ANA CON to justify a claim that ,SameCol' is transitive. But Fitch is not programmed to know about facts concerning the special subject matter of real numbers. So just as 13.35 adds the transitivy of 'SameCol' as a premise, you in your root-two proof will have to use statments of facts about numbers and operations on numbers as premises.
  • Feel free to discuss this problem via the course discussion board. I will delete inappropriate postings.

• For those experiencing problems with the Boole software: I have heard from the LPL people at CSLI that there are known difficulties with Boole in cases where people create a file on one platform (e.g. MAC) then submit it from a different platform (e.g. PC with Windows).

  So if you're experiencing difficulties with Boole, try sticking to one machine or one operating system, or at the very least, one platform. Please report any bugs you experience to the people at LPL: LPLbugs@csli.stanford.edu. Include the details of your operating system.

• Sections: Sections normally take place on Fridays at 2:30. There are three sections for the course.

  Section I: F 2:30-3:20 Goldwin Smith Hall 142 (Last name: A - E)
  Section II: F 2:30-3:20 Rockefeller 102 (Last name: F - Le)
  Section III: F 2:30-3:20 Goldwin Smith Hall G24 (G for ground level, but it's really the basement) (Last name: Li - Z)
  

  Please note: we assign you to a section on the basis of your last name, in order to even out class sizes. You should go to the room of the section we assign you to, irrespective of which section you "officially" signed up for.
   
• Note that for problem set 1, you are to do exercise 2.11 instead of 2.14. (The posting contained a typo on Monday that was fixed on Tuesday.)

Course Discussion Board!

This page created by Delia Graff
URL: http://instruct1.cit.cornell.edu/research/graff/phil231/announcements03.html
Last modified: "Sunday, 01 Jan 06, 13:55"