Logic: Negating if then statement

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Homework Help Overview

The discussion revolves around negating an if-then statement in logic, specifically the expression (p ∨ q) → (p ∧ q). Participants are exploring the correct approach to negation and the implications of logical equivalences.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants are attempting to understand how to properly negate the statement and whether negating both sides is appropriate. There are discussions about using De Morgan's laws and the implications of different logical forms.

Discussion Status

Some participants have provided guidance on how to approach the negation, suggesting the use of alternative logical expressions. There is an acknowledgment of confusion among newer participants regarding the notation and steps involved. The conversation reflects a mix of interpretations and attempts to clarify the process.

Contextual Notes

One participant notes the importance of adhering to forum rules regarding assistance, emphasizing the need for individuals to work through the problems themselves. There is also a request for clearer notation and step-by-step breakdowns, indicating a need for more accessible explanations.

mohabitar
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I'm trying to negate this statement and want to make sure I'm doing it right.
(p\veeq) ---> (p \wedge q)

So I don't negate both sides do I or else that would just make them equal out again? So I just negated the left side, so \neg(p\veeq) is equivalent to \negp\wedge\negq

So that's the answer I got:
\negp\wedge\negq ---> (p \wedge q)
 
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p=>q = ~p or q

Using de morgans law : ~(p=>q) = ~(~p or q) = p and ~q

So ~(p or q implies p and q) = p or q and ~(q and p) -> p or q and ~q or ~p -> p xor q
 
Sorry I am new to all this and what you have up there is very confusing. I can't really tell what's going on and what the final answer is. Anyway you can use the actual math symbols and break the steps into separate lines? I'd really appreciate it :)
 
JonF's already done too much work for you. It's against the forum rules to simply do the problems for you. You're supposed to work them out yourself.

Use the fact that you can write p→q as (~p)∨q. The latter form is easier to see how to negate.
 
Ya you're right sorry..I was just having a hard time understanding the symbols he was using but I think I got it now..so the final answer I got was:

(p v q) ^ (~p v ~q)

Is this what you had?
 
That's correct. You can simplify it a bit if you want.
 

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