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I have to deteremine whether each of the following expressions is a well-formed expression of statement logic or not 

(a) (r ∧ ¬r)
(b) q
(c) ¬( p) ∨ (q <-> p)
(d) ( p ∧ (q ∧ r) ∨ p)
(e) ∧ → pq
(f) ((r ∧ (q → p)) → r)

So my answers

(a) formula
(b) formula(any atomic statement is a wff
(c) not a formula (no parethesis around atomic statement)
(d) ? not a formula
(e) not a formula
(f) well-formed formula

I am not sure about (d). Perhaps somebody can explain it and check the rest?

user3077612
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1 Answers1

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Everything is right. D is not a formula. $p\land (q \land r) \lor p$ can mean $(p\land (q \land r)) \lor p$ or $p\land( (q \land r) \lor p) $, which are two different things.

user152102
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