What is the negation of $pto sim q$?












2












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I know that the negation of $pto q$ is ~p V q but I can’t seem to figure out the effect $sim q$ will have on the negation. Also is their a way to check if something is the negation of a statement?










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  • 1




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    Welcome to Maths SX! I'm sorry, but the negation of $pto q$ is $pwedge ({sim}q)$ since $pto q$ is $({sim}p)vee q$.
    $endgroup$
    – Bernard
    Jan 22 at 21:57








  • 2




    $begingroup$
    The negation for $pto q$ is $plandlnot q$. So by substitution ...
    $endgroup$
    – Graham Kemp
    Jan 22 at 21:59












  • $begingroup$
    Caution. The negation of $pto q$ is ${sim (p}to q)$ but it is not $({sim p})to q$. Which did you mean when you wrote ${sim p}to q$? So in the same way, the negation of $p to sim q$ is $sim (p to sim q)$.
    $endgroup$
    – GEdgar
    Jan 22 at 22:44












  • $begingroup$
    Whoops meant to write the negation as ~p V q
    $endgroup$
    – Mikayla
    Jan 22 at 23:09
















2












$begingroup$


I know that the negation of $pto q$ is ~p V q but I can’t seem to figure out the effect $sim q$ will have on the negation. Also is their a way to check if something is the negation of a statement?










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    Welcome to Maths SX! I'm sorry, but the negation of $pto q$ is $pwedge ({sim}q)$ since $pto q$ is $({sim}p)vee q$.
    $endgroup$
    – Bernard
    Jan 22 at 21:57








  • 2




    $begingroup$
    The negation for $pto q$ is $plandlnot q$. So by substitution ...
    $endgroup$
    – Graham Kemp
    Jan 22 at 21:59












  • $begingroup$
    Caution. The negation of $pto q$ is ${sim (p}to q)$ but it is not $({sim p})to q$. Which did you mean when you wrote ${sim p}to q$? So in the same way, the negation of $p to sim q$ is $sim (p to sim q)$.
    $endgroup$
    – GEdgar
    Jan 22 at 22:44












  • $begingroup$
    Whoops meant to write the negation as ~p V q
    $endgroup$
    – Mikayla
    Jan 22 at 23:09














2












2








2





$begingroup$


I know that the negation of $pto q$ is ~p V q but I can’t seem to figure out the effect $sim q$ will have on the negation. Also is their a way to check if something is the negation of a statement?










share|cite|improve this question











$endgroup$




I know that the negation of $pto q$ is ~p V q but I can’t seem to figure out the effect $sim q$ will have on the negation. Also is their a way to check if something is the negation of a statement?







propositional-calculus






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edited Jan 23 at 7:23









Mauro ALLEGRANZA

67k449115




67k449115










asked Jan 22 at 21:53









MikaylaMikayla

114




114








  • 1




    $begingroup$
    Welcome to Maths SX! I'm sorry, but the negation of $pto q$ is $pwedge ({sim}q)$ since $pto q$ is $({sim}p)vee q$.
    $endgroup$
    – Bernard
    Jan 22 at 21:57








  • 2




    $begingroup$
    The negation for $pto q$ is $plandlnot q$. So by substitution ...
    $endgroup$
    – Graham Kemp
    Jan 22 at 21:59












  • $begingroup$
    Caution. The negation of $pto q$ is ${sim (p}to q)$ but it is not $({sim p})to q$. Which did you mean when you wrote ${sim p}to q$? So in the same way, the negation of $p to sim q$ is $sim (p to sim q)$.
    $endgroup$
    – GEdgar
    Jan 22 at 22:44












  • $begingroup$
    Whoops meant to write the negation as ~p V q
    $endgroup$
    – Mikayla
    Jan 22 at 23:09














  • 1




    $begingroup$
    Welcome to Maths SX! I'm sorry, but the negation of $pto q$ is $pwedge ({sim}q)$ since $pto q$ is $({sim}p)vee q$.
    $endgroup$
    – Bernard
    Jan 22 at 21:57








  • 2




    $begingroup$
    The negation for $pto q$ is $plandlnot q$. So by substitution ...
    $endgroup$
    – Graham Kemp
    Jan 22 at 21:59












  • $begingroup$
    Caution. The negation of $pto q$ is ${sim (p}to q)$ but it is not $({sim p})to q$. Which did you mean when you wrote ${sim p}to q$? So in the same way, the negation of $p to sim q$ is $sim (p to sim q)$.
    $endgroup$
    – GEdgar
    Jan 22 at 22:44












  • $begingroup$
    Whoops meant to write the negation as ~p V q
    $endgroup$
    – Mikayla
    Jan 22 at 23:09








1




1




$begingroup$
Welcome to Maths SX! I'm sorry, but the negation of $pto q$ is $pwedge ({sim}q)$ since $pto q$ is $({sim}p)vee q$.
$endgroup$
– Bernard
Jan 22 at 21:57






$begingroup$
Welcome to Maths SX! I'm sorry, but the negation of $pto q$ is $pwedge ({sim}q)$ since $pto q$ is $({sim}p)vee q$.
$endgroup$
– Bernard
Jan 22 at 21:57






2




2




$begingroup$
The negation for $pto q$ is $plandlnot q$. So by substitution ...
$endgroup$
– Graham Kemp
Jan 22 at 21:59






$begingroup$
The negation for $pto q$ is $plandlnot q$. So by substitution ...
$endgroup$
– Graham Kemp
Jan 22 at 21:59














$begingroup$
Caution. The negation of $pto q$ is ${sim (p}to q)$ but it is not $({sim p})to q$. Which did you mean when you wrote ${sim p}to q$? So in the same way, the negation of $p to sim q$ is $sim (p to sim q)$.
$endgroup$
– GEdgar
Jan 22 at 22:44






$begingroup$
Caution. The negation of $pto q$ is ${sim (p}to q)$ but it is not $({sim p})to q$. Which did you mean when you wrote ${sim p}to q$? So in the same way, the negation of $p to sim q$ is $sim (p to sim q)$.
$endgroup$
– GEdgar
Jan 22 at 22:44














$begingroup$
Whoops meant to write the negation as ~p V q
$endgroup$
– Mikayla
Jan 22 at 23:09




$begingroup$
Whoops meant to write the negation as ~p V q
$endgroup$
– Mikayla
Jan 22 at 23:09










1 Answer
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$begingroup$

The definition of implication in propositional logic can be expressed with



begin{equation}tag{1}
prightarrow q~:=~(sim p)lor q
end{equation}



By this definition, the negation of $prightarrow q$ is $pland(sim q)$. This means that the statement $p$ implies $q$, is false only when the antecedent or premise of the statement is true, and its consequent false.



Using the same definition, negation of the statement $prightarrow (sim q)$ is



begin{align}
sim(prightarrow (sim q))~~~&Start\
sim((sim p)lor (sim q))~~~&Substitute~(1)\
pland q~~~&De~Morgan's~law
end{align}



To check if any two statements in propositional logic are the negation of one another, it is sufficient to substitute all instances of implication with the first definition, then negate one, and apply De Morgan's law successively to it until one reduces to the other. If this is the case, then they are negations of one-another.






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    0












    $begingroup$

    The definition of implication in propositional logic can be expressed with



    begin{equation}tag{1}
    prightarrow q~:=~(sim p)lor q
    end{equation}



    By this definition, the negation of $prightarrow q$ is $pland(sim q)$. This means that the statement $p$ implies $q$, is false only when the antecedent or premise of the statement is true, and its consequent false.



    Using the same definition, negation of the statement $prightarrow (sim q)$ is



    begin{align}
    sim(prightarrow (sim q))~~~&Start\
    sim((sim p)lor (sim q))~~~&Substitute~(1)\
    pland q~~~&De~Morgan's~law
    end{align}



    To check if any two statements in propositional logic are the negation of one another, it is sufficient to substitute all instances of implication with the first definition, then negate one, and apply De Morgan's law successively to it until one reduces to the other. If this is the case, then they are negations of one-another.






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      The definition of implication in propositional logic can be expressed with



      begin{equation}tag{1}
      prightarrow q~:=~(sim p)lor q
      end{equation}



      By this definition, the negation of $prightarrow q$ is $pland(sim q)$. This means that the statement $p$ implies $q$, is false only when the antecedent or premise of the statement is true, and its consequent false.



      Using the same definition, negation of the statement $prightarrow (sim q)$ is



      begin{align}
      sim(prightarrow (sim q))~~~&Start\
      sim((sim p)lor (sim q))~~~&Substitute~(1)\
      pland q~~~&De~Morgan's~law
      end{align}



      To check if any two statements in propositional logic are the negation of one another, it is sufficient to substitute all instances of implication with the first definition, then negate one, and apply De Morgan's law successively to it until one reduces to the other. If this is the case, then they are negations of one-another.






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        The definition of implication in propositional logic can be expressed with



        begin{equation}tag{1}
        prightarrow q~:=~(sim p)lor q
        end{equation}



        By this definition, the negation of $prightarrow q$ is $pland(sim q)$. This means that the statement $p$ implies $q$, is false only when the antecedent or premise of the statement is true, and its consequent false.



        Using the same definition, negation of the statement $prightarrow (sim q)$ is



        begin{align}
        sim(prightarrow (sim q))~~~&Start\
        sim((sim p)lor (sim q))~~~&Substitute~(1)\
        pland q~~~&De~Morgan's~law
        end{align}



        To check if any two statements in propositional logic are the negation of one another, it is sufficient to substitute all instances of implication with the first definition, then negate one, and apply De Morgan's law successively to it until one reduces to the other. If this is the case, then they are negations of one-another.






        share|cite|improve this answer









        $endgroup$



        The definition of implication in propositional logic can be expressed with



        begin{equation}tag{1}
        prightarrow q~:=~(sim p)lor q
        end{equation}



        By this definition, the negation of $prightarrow q$ is $pland(sim q)$. This means that the statement $p$ implies $q$, is false only when the antecedent or premise of the statement is true, and its consequent false.



        Using the same definition, negation of the statement $prightarrow (sim q)$ is



        begin{align}
        sim(prightarrow (sim q))~~~&Start\
        sim((sim p)lor (sim q))~~~&Substitute~(1)\
        pland q~~~&De~Morgan's~law
        end{align}



        To check if any two statements in propositional logic are the negation of one another, it is sufficient to substitute all instances of implication with the first definition, then negate one, and apply De Morgan's law successively to it until one reduces to the other. If this is the case, then they are negations of one-another.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Jan 22 at 23:35









        user400188user400188

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