(∀X)[Px ⊃ (∃Y)Qxy] ⊃ [(∃X)Px ⊃ (∃X)(∃y)Qxy]

question 201

Multiple Choice

(∀x) [Px ⊃ (∃y) Qxy] ⊃ [(∃x) Px ⊃ (∃x) (∃y) Qxy]
-Consider assuming '(∀x) [Px ⊃ (∃y) Qxy]' for a conditional proof of the above logical truth. Which of the
Following propositions is a legitimate second step in that proof?

• A) Assume '(∃x)Px' for a nested indirect proof.
• B) Assume '(∃x)(∃y)Qxy' for a nested indirect proof.
• C) Assume '(∃x)Px' for a nested conditional proof.
• D) Assume '(∃x)(∃y)Qxy' for a nested conditional proof.
• E) Px ⊃ (∃y)Qyy

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