Other
COS3761 Assignment 3(QUIZ) 2023 - suggested answers
- Course
- Institution
Complete highlighted answers to each question. Carefully researched and ensured correct. Guaranteed to get you an A the first try,
[Show more]
Seller
Follow
UnisaGuides
Reviews received
Content preview
COS3761Assignment 3
2023
Disclaimer
These study notes are meant to assist students and provide guidance for assignments.
They are not a substitute for individual research or professional advice. Accuracy of the
content is not guaranteed and it’s the buyer’s responsibility to verify it. Students must
uphold academic integrity and adhere to their institution’s policies on plagiarism. The
notes may not cover all variations of a subject matter, so students should tailor their
assignments accordingly. The seller is not liable for any negative outcomes from the use
of these notes. By using these notes, you agree to this disclaimer.
Thank you for choosing UnisaGuides. Please leave a review on the Stuvia platform about
the document you purchased. Your feedback helps us improve and assists other students.
ASSIGNMENT 3
Please note: This is an MCQ assignment – called a Quiz on myUnisa. There are 20 questions in this
assignment, each counting 5 marks. For each question, choose one out of the four options.
Unisa Guides
, x2
x₁
p p, q x₃
q
x₄
Figure 1: Kripke model used in Questions 1 to 5 QUESTION
In which world of the Kripke model in Figure 1 is the formula ◊ p ∧ □ q true?
Option 1: world x₁
Option 2: world x₂
Option 3: world x₃ ✅
Option 4: world x4
• The formula ◊ p means that there is a possibility of ‘p’ being true in the current world or
some accessible world. In world x3, ‘p’ is true.
• The formula □ q means that ‘q’ is true in the current world and all its accessible worlds.
In world x3, ‘q’ is true and it’s also true in its accessible world (x4).
QUESTION 2
Which of the following does not hold in the Kripke model in Figure 1?
Option 1: x₁ ◊◊p
Option 2: x₂ □p✅
Option 3: x₃ □p∧□q
Option 4: x₄ □□ p
• The formula □ p means that ‘p’ is true in the current world and all its accessible worlds. In
world x2, ‘p’ is not labelled, which means ‘p’ is not true in this world. Therefore, □ p does not
hold in world x2.
, QUESTION 3
Which of the following holds in the Kripke model given in Figure 1?
Option 1: x₁ □p
Option 2: x₂ ◊ (p → q)
Option 3: x₃ ◊p∨□¬q
Option 4: x₄ ◊ (p ∨ q) ✅
The formula ◊ (p ∨ q) means that there is a possibility of either ‘p’ or ‘q’ being true in the current world
or some accessible world. In world x4, ‘q’ is true. Therefore, ◊ (p ∨ q) holds in world x4
QUESTION 4
Which of the following formulas are satisfied by the Kripke model given in Figure 1?
Option 1: ◊ p ✅
Option 2: □q
Option 3: □ (p ∨ q)
Option 4: ◊p∨q
This formula means that there is a possibility of ‘p’ being true in some world. In the Kripke model you
described, ‘p’ is true in worlds x1 and x3. Therefore, the formula ◊ p is satisfied by the Kripke model.
QUESTION 5
Which of the following formulas are not satisfied by the Kripke model given in Figure 1?
Option 1: □ p ∨ ◊ q
Option 2: □◊p ✅
Option 3: q∨◊¬q
Option 4: p∨□q
This formula means that ‘p’ is true in the current world or ‘q’ is true in all worlds. In the Kripke model
you described, ‘p’ is not true in all worlds (it’s not true in x2 and x4), and ‘q’ is also not true in all worlds
(it’s not true in x1 and x2). Therefore, this formula is not satisfied by the Kripke model.
QUESTION 6
If we interpret □ φ as "It ought to be that φ ", which of the following formulas correctly expresses the
English sentence
If it is permitted that politicians can break the law, then it ought not to be the case that we are
punished for breaking the law.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller UnisaGuides. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $2.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
78121 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now