1. Here is a model:
Domain: {Wikipedia, 2, Isaac Newton}
Referents: n: Isaac Newton
Extensions: P: Ø Q: {2} R: {Wikipedia, Isaac Newton}
Is the following proposition true or false on this model?
Explain your answer.
∀x(Qx ∨Rx) → Pn
2. Is the following argument valid or invalid? If it is valid,
explain why there cannot be a countermodel. If it is invalid,
provide a countermodel.
ᄀ∀xHx
∃xMx
∴ᄀ∃x(Mx ∧Hx)