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Help in natural deduction
- Thread starter searcher_
- Start date
D
Deleted member 4993
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I need help to solve the follow natural deduction => ∃x∀y ¬α(x, y) ➔ ¬∀x∃y α(x, y)
¬∀x∃y α(x, y) I ➔
∃x∀y ¬α(x, y) ➔ ¬∀x∃y α(x, y)
This is the two last lines...
I would like to understand step by step
¬∀x∃y α(x, y) I ➔
∃x∀y ¬α(x, y) ➔ ¬∀x∃y α(x, y)
This is the two last lines...
I would like to understand step by step
What does that mean?This is the two last lines...
Code:
[∃x∀y ¬α(x, y)] [¬∀x∃y α(x, y)]
... ...
¬∀x∃y α(x, y) ∃x∀y ¬α(x, y)
___________________________________I➔ ___________________________________I➔
∃x∀y ¬α(x, y) ➔ ¬∀x∃y α(x, y) ¬∀x∃y α(x, y) ➔ ∃x∀y ¬α(x, y)
____________________________________________________________________________I↔
∃x∀y ¬α(x, y) ↔ ¬∀x∃y α(x, y)Code:[∃x∀y ¬α(x, y)] [¬∀x∃y α(x, y)] ... ... ¬∀x∃y α(x, y) ∃x∀y ¬α(x, y) ___________________________________I➔ ___________________________________I➔ ∃x∀y ¬α(x, y) ➔ ¬∀x∃y α(x, y) ¬∀x∃y α(x, y) ➔ ∃x∀y ¬α(x, y) ____________________________________________________________________________I↔ ∃x∀y ¬α(x, y) ↔ ¬∀x∃y α(x, y)
just the last lines of natural deduction to explain the format