April 24th 2020

• Both video recording and notes are now available on Blackboard for today's lecture.

April 22nd 2020

• Both video recording and notes are now available on Blackboard for today's lecture, along with some extra worked examples on using Rule I in its various forms.
• Assignment 11 grading and results are now available to view in Gradescope (link in Blackboard ).
• The Course Evaluation window is now open. Please take the time to give your feedback. Constructive criticism and support for things that worked well are welcome.
• Those who are graduating should be aware about the possibilities associated with a virtual Commencement Ceremony. Please make sure that you get the celebration you deserve!

April 20th 2020

• Both video recording and notes are now available on Blackboard for today's lecture.

April 19th 2020

• The results from the second midterm assessment are now available through Blackboard , with grading breakdowns and feedback available in Gradescope (link in Blackboard ). The solutions are also available on Blackboard (in the "Worked Solutions" folder).
• Since I want to be sure that your overall final grade best represents your overall achievements and understanding in this course, in the face of disruptions experienced by everyone to some degree or other during the course of this semester, I am announcing the following as the way in which the 25% "Assignments" portion of your final grade will be calculated: it will be based on the highest 9 out of the 12 assignment scores, i.e. the lowest three scores will not be used as part of the calculation (those assignments not submitted will be given a score of 0 for the purposes of this calculation).
• The final assignment, Assignment 12, is now posted below under Assessments. It is due at 10:30am EDT on Friday April 24th 2020. It should be submitted via Gradescope (link in Blackboard ).
• Virtual Zoom office hours this week will be at the usual times, namely Tuesday April 21st 2-3pm, Wednesday April 22nd 2:30-3:30pm and Thursday April 23rd 4-5pm.

April 17th 2020

• Both video recording and notes are now available on Blackboard for today's lecture.
• The grading of Test 2 was unfortunately delayed due to a bug in Gradescope that deleted some of the grading already completed, which then had to be recovered manually by the nice people at Gradescope. The grading should be finished and released later today, or as soon as possible over the weekend.

April 15th 2020

• Both video recording and notes are now available on Blackboard for today's lecture.
• Regarding the current Assignment 11, please see a document to be found on Blackboard (in the "Assignments" folder) with some hints on the problems, including guidance about how to give your answers using the material from class (especially Lectures 31, 34 and 35), and some further worked examples. These provide some parts of some of the answers, so are well worth a look.

April 13th 2020

• Assignment 11 is now posted below under Assessments. It is due at 10:30am EDT on Friday April 17th 2020. It should be submitted via Gradescope (link in Blackboard ).
• Both video recording and notes are now available on Blackboard for today's lecture.
• Virtual Zoom office hours this week will be at the usual times, namely Tuesday April 14th 2-3pm, Wednesday April 15th 2:30-3:30pm and Thursday April 16th 4-5pm.

April 9th 2020

• The second midterm assessment is now available on Blackboard . The deadline for submitting answers to Gradescope (link in Blackboard ) is Friday April 10th 2020, 9pm EDT.

April 8th 2020

• Both video recording and notes are now available on Blackboard for today's lecture.
• A reminder: there will be no lecture on Friday April 10th 2020 while the second midterm assessment is being carried out.
• Thanks to everyone who "checked their tech" by trying out the Fake Test practice exercise. If you found any difficulties, please let me know. If you submitted something for this exercise, then you should have received an email with feedback from me by now (please let me know if you didn't).
• Some of the solutions to the Suggested Problems for the second midterm assessment are now posted on Blackboard ; more will be posted after they are ready to upload.
• Assignment 10 grading and results are now available to view in Gradescope (link in Blackboard ).
• Remember, while the second midterm assessment is running, you will not be able to collaborate or communicate with anyone about the test until after the deadline. In particular, this means that you will not be allowed to post any questions on Piazza during that time. Therefore, if you have questions, make sure that you post them early enough that you might get answers before the assessment starts!

April 6th 2020

• The details of the practice for test assignments (the "Fake Test") has now been circulated via email. Please let me know if you did not get the email. This practice is designed to make sure that everyone is set up with a mechanism for carrying out test assignments remotely. Please go to Blackboard and find the "Fake Test Paper," and follow the instructions therein for submitting your "answers" via Gradescope (link in Blackboard ) by the Fake Test deadline of Tuesday April 7th 2020 11:59pm.
• Both video recording and notes are now available on Blackboard for today's lecture.

April 5th 2020

• A list of suggested practice problems for the second midterm assessment is available below, under Assessments.
• Assignment 9 grading and results are now available to view in Gradescope (link in Blackboard ).
• Virtual Zoom office hours this week will be at the usual times, namely Tuesday April 7th 2020 2-3pm, Wednesday April 8th 2020 2:30-3:30pm and Thursday April 9th 2020 4-5pm.

April 3rd 2020

• Both video recording and notes are now available on Blackboard for today's lecture.
• There will be a practice run for the second midterm assessment early next week, where a fake test paper will be posted to Blackboard and you will be asked to test your technology by uploading your "solutions" to the fake test to Gradescope (link in Blackboard ) by a given fake test deadline. Please stay tuned for more details, which will also be announced by email.

April 1st 2020

• Both video recording and notes are now available on Blackboard for today's lecture, as well as the extra proof that we didn't have time to cover. Unfortunately, there were some audio problems during today's lecture, and so the video upload was delayed (the recording required some serious editing which has taken most of the day to process and compile).

March 30th 2020

• Virtual Zoom office hours this week will be at (almost) the usual times, namely Tuesday March 31st 2:30-3:30pm, Wednesday April 1st 2:30-3:30pm and Thursday April 2nd 4-5pm.
• Both video recording and notes are now available on Blackboard for today's lecture. (There are also some supplementary notes posted for those interested in thinking more about the equivalence of different formulations of "semantic equivalence" and "logical equivalence.")
• An email was just sent out to the entire class concerning arrangements for the assessment "Midterm Test 2." Please let me know if you did not receive this. The key details are as follows:
  • The test will be an open-book, written assessment. In this context, open book means that you may consult the textbook, your lecture notes, and any previous work from the course that you have done, but are NOT ALLOWED to collaborate or to communicate in any way about the test with anyone else, either inside or outside the class. In these times, I will be relying more than ever on your honor to uphold these rules.
  • The scope of the material will be Chapters 6-9 (i.e. the material covered by the Assignments 6-9) as well as the definitions of logical theorem, logical implication and logical equivalence from the start of Chapter 10.
  • The test paper will be posted to Blackboard at 6pm EDT on Thursday April 9th 2020, and you will have until 9pm EDT on Friday April 10th 2020 to submit your answers via Gradescope (link in Blackboard ).
  • Although you have a 27 hour time window in which to complete the test, you should expect to spend no more than around 90 minutes in total completing it. (But you are allowed to take longer if you wish.)
  • If possible, please write out your answers on the test paper itself (either by printing the test paper, then completing the test and scanning it in, or by working on the test paper file electronically). Of course you may also add in extra pages if you need to do so, but please make sure that they appear in the correct place, clearly identified. (If you cannot print, or cannot write on the electronic file, then proceed as you would with an assignment, but please try to match the layout of the original test file as closely as possible so that your submission might still be correctly processed by Gradescope – in particular, your submission will need to have at least as many pages as the test file in order to be accepted.)
  • There will be NO lecture on Friday April 10th 2020 while this Midterm Test 2 assessment is being carried out.
  • Some suggested practice problems will be posted on this page in advance of this Midterm Test 2 assessment, with answers uploaded to Blackboard on Thursday April 9th 2020 at the latest.
  • The lectures on Monday April 6th 2020 and Wednesday April 8th 2020 will be review sessions, so please post suggestions on Piazza (accessed through Blackboard ) of questions/topics to cover during those review sessions. Please weigh in with support for any suggestions that you like, as well as post any new ones you have. (Note, there is a folder in Piazza called test2review that you can use to post suggestions.)
• The format for the Final Examination assessment is expected to be similar to the format of the Midterm Test 2 assessment. The exam will be cumulative (scope to be announced), and the deadline will be during Finals Week. The exam will be longer than Midterm Test 2 so the time window to complete will correspondingly be longer. The exact details will be circulated closer to the time, after they have been confirmed.

March 29th 2020

• Assignment 10 is now posted below under Assessments. It is due at 10:30am EDT on Friday April 3rd 2020. It should be submitted via Gradescope (link in Blackboard ).

March 27th 2020

• Both video recording and notes are now available on Blackboard for today's lecture.

March 25th 2020

• Assignment 8 grading and results are now available to view in Gradescope (link in Blackboard ).
• Both video recordings and notes are now available on Blackboard for Monday's and today's lectures.
• If you have not already told me (via email) which time zone you will be in for the remainder of the semester, please communicate to me whatever you can about this as soon as possible (I was seeking feedback by the end of today). This will assist greatly with arrangements for assessments to stand in for the in-person written "Midterm Test 2" and "Final Examination".

March 22nd 2020 -- update

• Assignment 9 is now posted below under Assessments. It is due at 10:30am EDT on Friday March 27th. It should be submitted via Gradescope (link in Blackboard ).

March 22nd 2020

• Another update email was just circulated to course participants concerning further details of changes to course delivery starting tomorrow. If you did not receive this, please let me know. If you are auditing the course without enrolling, and so do not have access to Blackboard yet, please email me.
  The key details are as follows:
• Lectures will continue to take place at the regularly scheduled times, but you are henceforth NOT ALLOWED to attend in person. They will be recorded via Boilercast, as long as the capacity of the system allows for this, and the clasroom remains available. These recordings will be made available through Blackboard , and they will also be live-streamed through Zoom for those who are able to participate. Details of how to connect to the lectures through Zoom are available on Blackboard . The notes made during lectures will also be scanned and posted to Blackboard .
• It will likewise no longer be possible to attend office hours in person. "Live" office hours will likewise be live-streamed via Zoom (details, as above, to be found on Blackboard ). The exact times of these Zoom office hours will likely vary slightly from week to week according to the availability of the equipment at my end; however, they will be as close as possible to the previous office hour times. This week, Zoom office hours will be on Wednesday March 25th 2020 2:30-4pm and on Thursday March 26th 2020 4-5:30pm.
• There is also a Piazza discussion board for this class now accessible through Blackboard . I plan to check this on a regular basis. Please ask questions there, answer them, and generally use this as a forum of discussion about topics of the course.
• Since no further assessments may now be conducted in person, a decision will be taken later this week about the nature of the assessments currently called "Midterm Test 2" and "Final Examination". This partly depends on the following:
• If you did not already email me to tell me which time zone you will be in for the remainder of the semester, please do so by Wednesday March 25th 2020. If I do not hear from you (whatever you can tell me at this stage), then I will plan according to the assumption that you are in the same time zone as the Purdue main campus.

March 12th 2020

• An email was just circulated to all course participants concerning changes being made to the way in which this course will be delivered, effective immediately. Please let me know if you did not receive this email. The most pressing information is as follows:
• Effective immediately, assignments are to be submitted electronically via Gradescope, which can be accessed through Blackboard (the link to Gradescope is in the left-hand menu; instructions, if you need them, for scanning and uploading your work to Gradescope can be found on in the "Assessments" folder). Since this requires a new approach, and you may need extra time to set this up, the deadline for Assignment 8 has been extended by 24 hours until this Saturday March 14th, 10:30am.
• Following Spring Break, instruction for this course will move online. Virtual "lectures" are planned through an online platform (to be determined; instructions for accessing these will be circulated in due course). However, it might not be possible to keep to the currently scheduled lecture times, as perhaps not all participants will remain in the same time zone as Purdue's main campus (EDT). Everyone is requested to email me as soon as possible to indicate which time zone they will be in following Spring Break, or provide whatever relevant information that they can at this time.
• The schedule of assessments has been modified. Please take note of the new schedule below.
• These circumstances present significant challenges for all of us, and I recognize that the current circumstances may cause distress. Please let me know if you have any particular concerns, and, in case at any time any of you finds yourself struggling or overwhelmed, please remember that Purdue support services remain available for the foreseeable future, in particular Counseling and Psychological Services (CAPS). For further information and links, please see below.

March 11th 2020

• Assignment 7 was handed back in class today. Due to the planned change in course delivery following Spring Break, you have one more chance this semester to come and collect either Test 1 or Assignments 1-7 from me, and that is during the office hour on Thursday March 12th, 3:15-4:15pm.
• Please know that, due to circumstances beyond my control, measures will need to be implemented to change the syllabus and planned running of this course for the remainder of the semester. As soon as I have more information for you, I will let you know, both through this website and, if it is urgent, via your Purdue email, so please keep checking both. (Don't forget to refresh your browser on this page; sometimes the newest update doesn't load automatically.)
• In particular, you may be asked already to submit Assignment 8 online THIS week via some means to be determined. Please keep an eye out for notices regarding this, as I will provide instructions if this becomes the case. (The goal is to do this now, if possible, in order to facilitate returning your work to you following Spring Break.)
• A note on Rule EP: since we covered this more hurriedly than planned in class today (owing to the need to spend time discussing contingency measures), I have posted a complete version of the final (long) worked example that we covered today on Blackboard , together with notes on the correct statement of the Rule EP (at times in class today certain key details were not stated fully, which I recognize could have been confusing, so please see the posted file for the correct statements).
• If you have any concerns or questions about the developments on campus and what they will mean for this course, please don't hesitate to get in touch. I will do my best to get you whatever answers I can, and would appreciate your patience while all of this is being worked out.

March 10th 2020 -- update

• Spoke too soon.
  • Update on remaining office hours this week: these will be on Wednesday March 11th 2020 2:15-3:15pm and Thursday March 12th 3:15-4:15pm.
  • Following the university's announcement today that the delivery of courses after Spring Break should move online, discussions are currently taking place to identify the best means to enable this to happen. Please keep an eye out for further announcements regarding what that means for this course, both on this site and in class later this week.

March 10th 2020

• Office Hour for this Thursday is, as in the past couple weeks, moved to 3:15-4:15pm. This should be the last time that this happens, and usual hours (below) will resume after Spring Break.

March 9th 2020

• Assignment 8 is now posted below (under "Assessments"). It is due at the start of class on Friday March 13th.
• Office hours this week are as usual on Tuesday and Wednesday, but may be adjusted on Thursday as in the past two weeks. Please stand by for more information (and double check this website before heading to office hours).
• Assignment 6 was returned in class today; you may collect it during office hours if you did not pick it up today.

March 4th 2020

• Office hours this week: on Thursday March 5th 2020 this is moved to 3:15-4:15pm. (Times on Tuesday and Wednesday remain unchanged.)
• The two worked examples on Chapter 7 (Rules US and UG) that we didn't have time to cover in class today are now posted on Blackboard . Please try them first before looking at the solutions!

March 1st 2020

• Happy St David's Day everyone! Assignment 7 is now posted below (under "Assessments"). It is due at the start of class on Friday March 6th.

February 28th 2020

• The notes on what it means for a tuple $\bar{a}$ in a universe $U$ from a structure $\mathcal{S}$ to satisfy a formula $\phi$ are now uploaded to Blackboard .

February 26th 2020 -- update

• With apologies for the short notice, the changed time as previously announced for office hours on Thursday February 27th 2020 was incorrect (being based on some incorrect information, now corrected); the correct time should be 3:00-4:15pm.

February 26th 2020

• Midterm Test 1 was returned in class today, and the marks and solutions are posted on Blackboard . If you want to collect your test you may do so during office hours. Approximate grade cutoffs for Midterm Test 1: A 90; B 80; C 70. Average: 85.7. Please come and talk to me during office hours if you want to discuss it.

February 25th 2020

• Office Hours this week: Tuesday February 25th 2020 2:30-3:15pm, Wednesday February 26th 2020 2:30-3:30pm, Thursday February 27th 2020 4:30-5:45pm (see above).

February 24th 2020

• Assignment 6 is now posted below (under "Assessments"). Due at the start of class on Friday January 28th.
• Office hours this week are slightly altered: they will be on Tuesday February 25th 2020 2:30-3:15pm, and on Wednesday February 26th 2020 2:30-3:30pm and on Thursday February 27th 2020 at a time to be confirmed (stay tuned for further details).

February 20th 2020

• Worked solutions to the Suggested Problems for Midterm Test 1 from 5D, 5E and 5F are now posted on Blackboard . Sorry for the delay; I was aiming to post these earlier but there were problems saving them and they kept getting deleted. These last few have been done semi-old school!

February 19th 2020 -- update

• Worked solutions to the Suggested Problems for Midterm Test 1 from Chapters 1-4 and 5A are now posted on Blackboard . I am aiming to post worked solutions to the remainder of the Suggested Problems tomorrow.

February 19th 2020

• From class today: a word or two on writing formal proofs. If you're told that proofs should be "fully annotated" this means that on each line you should give:
  • a line number;
  • the rule used to produce the formula on that line (together with the line numbers of any previous formulae used, if relevant);
  • the numbers of the premises used on that line; and
  • if using Rule T, give the tautology used (it is sufficient to give the number of the tautology from the list; it is not necessary to write out the full tautology if it is on the list).
  Also, while we've said that you should only use the tautologies from the list for Rule T, (a) there is one exception, which is when you need to use the tautology $P \to P$ (not on the list) to take the conjunction of previous lines as a new line (e.g. you have proved $B$ and $\neg D$ and so you want to conclude $B \wedge \neg D$ -- this is allowed), and (b) while it might perhaps not receive full credit, it would almost certaintly be better to use a tautology not on the list and then proceed with the rest of the proof, than just to stop and not complete a formal proof because you couldn't find a tautology on the list that does what you want.
  Please let me know if you have any questions about this (or anything else).
• Assignment 5 was handed back today in class, so if you want to get this back (or any earlier assignment) then please come see me during office hours.
• Remember that office hours this week will be slightly rearranged: there will be extended office hours today, 2:30pm - 4pm, and on Thursday February 20th 2020, 4pm - 5:30pm.
• I aim to post at least some worked answers to the Suggested Practice Problems for Midterm 1 later today, and the rest tomorrow; stay tuned for more information.

February 16th 2020

• Office hours this week will be slightly rearranged: there will be no office hour on Tuesday (February 18th 2020) but there will be extended office hours on both Wednesday February 19th 2020, 2:30pm - 4pm, and on Thursday February 20th 2020, 4pm - 5:30pm.
• Just a reminder that we will spend time on review in class this week. We will mostly do this by going through problems, so please don't forget your textbook! I would aim to focus on problems from the assignments on Monday and not look at any of the suggested review problems before Wednesday, to give people time to attempt some of them. Please come with your requests for what you would like to see covered.

February 14th 2020

• Details for the first Midterm Test are posted below, on the schedule of assessments. Please email me or let me know in class or in office hours if you have any questions not answered by the information below. On Monday and Wednesday next week we will review material, preferably through doing problems, so please come with suggestions and we will try to do as many as we can.
• Included in the information about the test are some suggested practice problems. It is entirely up to you if you do these, but I hope that they help to orient you and focus your attention on key aspects of the material covered so far. One suggestion is, once you have studied and think you are comfortable with the material, to pick ten of these problems at random and try to complete them "under timed conditions" i.e. set aside 45 minutes, and go through them as if in an exam setting. I will post as many worked solutions to these problems as I can around the middle of next week (note that some have answers in the back of the textbook). (If you have any particular requests, please let me know -- see also the next bullet point.)
• I've had a small number of requests for each of the following: posting the notes from class, posting more worked examples, and changing the times of office hours. However, unfortunately, none of these things is totally straightforward to achieve, so I would only want to take action if there were a large voice of support for any of these (and not a large voice of support for keeping things as they are). Therefore, please feel free to let me know if you have an opinion (either way) about any of these points!
• Another reminder: if you require any accommodations for sitting the test, then please discuss these with me as soon as possible. You may have to arrange to sit the test through the DRC Testing Center, which you would then need to book without delay, so that everything can be set up in time. (Please see the information and the link below under Academic Accommodation of Students with Disabilities.)

February 12th 2020

• Assignment 4 was handed back in class today. Please see me during office hours if you would like to collect any assignment work that you have not yet collected. I would like to remind you that it is useful to go through your previous work as a learning exercise.
• Remember that the first Midterm Test is scheduled for Friday 21st 2020 in class. This means that it will be held in the regular classroom (at the usual class time) and will last 45 minutes. More information will be announced in class and posted here next week.
• Please already note: if you require any accommodations for sitting the test, then please discuss these with me as soon as possible. You may have to arrange to sit the test through the DRC Testing Center, which you would then need to book without delay, so that everything can be set up in time. (Please see the information and the link below under Academic Accommodation of Students with Disabilities.)
• At the end of this week (following Friday's class) I will inform you what the scope of the material for the first Midterm Test will be, and will also post (on this page) some suggested review problems on that material.
• Next week in class before the test, i.e. on Monday and Wednesday, we will review material covered so far. So please come equipped with your textbook and with suggestions of problems to cover (from past assignments, from the suggested review problems, etc.). We'll try to get through as many as possible, but we will first vote on the order in which we'll cover them.
• Finally, remember that the due date for Assignment 5 has been extended to the start of class on Monday 17th February, 2020.

February 10th 2020

• A reminder that the first Midterm Test is scheduled for Friday 21st 2020 in class. If you have an Accommodation Letter from DRC specifying any special accommodations, then please remember to contact me well in time, and you may need to book to take the test at the DRC Testing Center. In particular, please see the information and the link below under Academic Accommodation of Students with Disabilities.

February 7th 2020

• Assignment 5 is now posted below (under "Assessments"). Since the first midterm is coming up, there is some extra time for this one: Assignment 5 is due at the start of class on Monday February 17th.
• Information will be announced during the course of next week about the scope of material for the first midterm. This will certainly include everything that we have covered to date, and some of what we have yet to cover. Stay tuned for further announcements.

February 3rd 2020

• Assignment 4 is now posted below (under "Assessments"). Due at the start of class on Friday February 7th.

January 27th 2020

• Assignment 2 was handed back today in class, though right at the end, so I will also bring it again on Wednesday for those who couldn't stay to collect theirs. If you want to pick it up sooner than that, however, you may do so during office hours. We might go through some of the problems on Wednesday, if there is time, so be prepared to ask and we might take a vote on which problems to do.

January 26th 2020

• Assignment 3 is now posted below (under "Assessments"). Due at the start of class on Friday January 31st.

January 22nd 2020

• If you wish to collect any assignment work and are not in class when it is handed back, then you have to come to an office hour to collect it, i.e. $A \wedge \neg C \longrightarrow O$, where $A$: "You wish to collect assignment work"; $C$: "You are in class when it is handed back"; $O$: "You will have to come to an office hour to collect it". For fun, check that this is logically equivalent to $\neg A \vee C \vee O$ (and that you understand why this also makes sense from the point of view of the English)!
• The solutions to the assignments will not as a rule be posted, so if you want to discuss anything about them, please see me after class or come to office hours.
• The second chapter of the textbook is now available below (under "Course Information" --> "Textbook") along with the first chapter, for those who haven't got their copy yet (also see below for how to get access to a copy).

January 22nd 2020

• The course page on Blackboard is now up and running. Grades for tests and assignments will be available there (you can now see your grades for the first assignment, which will be returned in class today). However, announcements will be posted on this website so keep checking for more information.

January 20th 2020

• With apologies for the delay this week, Assignment 2 is now posted below (under "Assessments"). Due at the start of class on Friday January 24th.

January 13th 2020

• The first chapter of the textbook is available below (under "Course Information" --> "Textbook") for those who haven't got their copy yet (also see below for how to get access to a copy).
• Also the Blackboard page is not up and running yet so don't panic if you can't find it there! It will be announced here when that is available.

January 10th 2020

• Assignment 1 posted below (under "Assessments") -- please note that this is due Friday January 17th, i.e. in one week, i.e the first week of class! Assignments will consist of problems from the textbook (see below), to be handed in at the start of class each Friday (when there isn't a Midterm Test).
• During the first week of class, office hours will exceptionally be as follows: Monday January 13th, 2-3pm, and Tuesday January 14th, 2-3pm and 4-5pm.

January 9th 2020

• This page is up and running! Welcome to MA 38500.