PHIL1012 INTRODUCTION TO LOGIC
PROBLEM SET 6 (S2 2021)
Submit your answers to Problem Set 6 via Canvas before 23:59, Wednesday of Week 9.
1. Here is a model M :
Domain: {1, 2, 3, 4, 5}
P : {1, 3, 5}, Q : {2, 4, 5}, R : ∅, S : {3, 4}
a : 3, b : 4
Is the proposition ∀x((Px ∧Qx) → Sx) ∨ (Rb ↔ Pa) true or false in M? Explain.
2. Define a model in which all of the following propositions are true.
∃x(Gx ∧Hx)
∀yHy → ∃z¬Fz
Fk ↔ ∀x(Gx ∨ Fx)
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