Proving ∃x(P(x) → ∀y(P(y))): An Exercise in Logic

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SUMMARY

The discussion focuses on proving the logical statement ∃x(P(x) → ∀y(P(y))). Participants clarify that this statement is equivalent to ∃x(¬P(x) ∨ ∀y(P(y))). The exercise is part of a section on "proofs involving disjunctions" from the textbook "How to Prove It." Several users express difficulty in approaching the proof, with some attempting proof by contradiction but lacking confidence in their results.

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Homework Statement



Prove ∃x(P(x) → ∀y(P(y))).

Homework Equations





The Attempt at a Solution



∃x(P(x) → ∀y(P(y))) is equivalent to ∃x(¬P(x) ∨ ∀y(P(y))).



This exercise is found in a section on "proofs involving disjunctions." I have tried many different ways to solve this and have a feeling I am not approaching it the right way. Perhaps I am not considering clever enough exhaustive cases? Can anyone direct me in the proper way to begin?
 
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This is an exercise from "How to prove it" right?:biggrin:

I'm having troubles with this one too.

I've tried a proof by contradiction, i think i proved it but I'm not so sure.
 

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