COMP2022: Programming Languages, Logic and Models Assignment 3 Due: 23:59pm Tuesday 5th November 2019 This assignment can be completed individually, or in a pair of two students. Consider the following argument: 1− (¬A ∨B) 2− (¬C → B) 3− ((D ∧ C)→ A) ⊢ (¬B → ¬D) 1 Proofs 1.1 “Assignment Q1 (Conditional Proof)” Prove the argument using a conditional proof. • You must use CP at least once. • You cannot use IP in this proof. 1.2 “Assignment Q2 (Indirect Proof)” Prove the argument using an indirect proof. • You must use IP at least once. • You cannot use CP in this proof. 1.3 “Assignment Q3 (Direct Proof)” Prove the argument using a direct proof. • You cannot use IP or CP in this proof. • This is a bit more challenging than the previous two proofs! These questions have both been pre-loaded in the Logic Tutor, using the names quoted above. You must enter your proofs in the Logic Tutor, as answers to the corresponding questions. 2 Marking • Correctness: the first four marks are for producing correct proofs (divided evenly between the three questions). • Efficiency: the last mark are based on the length of your proofs. For each of the three questions, you will be assigned up to a third of a mark based on how long your shortest proof is compared to the other students! 1 Marking will be based on the shortest correct proof made by you (or by your partner, if in a pair) which satisfies these restrictions (i.e. it doesn’t need to be your most recent attempt, although it should be the one submitted to Canvas.) If you are unable to complete one of the proofs, you should submit your best attempt to canvas, as we may award partial marks if it shows significant progress towards a solution. 3 Submission details • Due: 23:59pm Tuesday 5th November 2019. • No submissions will be accepted more than one day late, as we will discuss the best proofs in the lecture. Alternative arrangements will be made in cases where Special Consideration is appropriate. • You are required to submit your proofs on both the Logic Tutor and on Canvas: 3.1 Canvas submission • On Canvas, you must submit a copy of your proofs (copy paste from the Logic Tutor, or take screenshots) • If you worked in a group, you must also include a signed assignment cover sheet in your submission, and you must join an assignment group on Canvas before submitting. • Details on this is included on the submission point in Canvas. 3.2 Proof submission on Logic Tutor Submit your proofs to the corresponding questions on the Logic Tutor website: • http://logic-comp2022.it.usyd.edu.au • Your login details were provided on tutorial sheet 10. • Reminder: you will need to use the VPN to access this if you are outside the university network. https://sydneyuni.service-now.com/sm?id=kb_article_view&sysparm_article=KB0011049 2
