Using inference to prove that $(pwedge q)vee (pwedge r) to (q vee r)$.












1












$begingroup$


Only using rules of inferences to prove that $(pwedge q)vee (pwedge r) to (q vee r)$



I tried to solve it with this:




  1. (p⋀q)⋁(p⋀r) (premise)

  2. (p⋀q) (Assumption)

  3. p (⋀-elimination)

  4. p⋀r (Assumption)

  5. p (⋀-elimination)

  6. p (⋁-elimination 3,5)


But this seems wrong. Does anyone else have a clue on which rules to apply for this? Thank you.










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    What rules of inference are you allowed to use? Impossible to answer without knowing this.
    $endgroup$
    – David
    Feb 1 at 3:42












  • $begingroup$
    Introduction rules and elimination rules
    $endgroup$
    – alice123019
    Feb 1 at 3:50










  • $begingroup$
    What have you tried? It is a fairly easy proof, so where are you having trouble?
    $endgroup$
    – Graham Kemp
    Feb 1 at 3:52










  • $begingroup$
    Do you have the distributive law?
    $endgroup$
    – vadim123
    Feb 1 at 4:10










  • $begingroup$
    Distributive law is not allowed to use in this question
    $endgroup$
    – alice123019
    Feb 1 at 4:12
















1












$begingroup$


Only using rules of inferences to prove that $(pwedge q)vee (pwedge r) to (q vee r)$



I tried to solve it with this:




  1. (p⋀q)⋁(p⋀r) (premise)

  2. (p⋀q) (Assumption)

  3. p (⋀-elimination)

  4. p⋀r (Assumption)

  5. p (⋀-elimination)

  6. p (⋁-elimination 3,5)


But this seems wrong. Does anyone else have a clue on which rules to apply for this? Thank you.










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    What rules of inference are you allowed to use? Impossible to answer without knowing this.
    $endgroup$
    – David
    Feb 1 at 3:42












  • $begingroup$
    Introduction rules and elimination rules
    $endgroup$
    – alice123019
    Feb 1 at 3:50










  • $begingroup$
    What have you tried? It is a fairly easy proof, so where are you having trouble?
    $endgroup$
    – Graham Kemp
    Feb 1 at 3:52










  • $begingroup$
    Do you have the distributive law?
    $endgroup$
    – vadim123
    Feb 1 at 4:10










  • $begingroup$
    Distributive law is not allowed to use in this question
    $endgroup$
    – alice123019
    Feb 1 at 4:12














1












1








1





$begingroup$


Only using rules of inferences to prove that $(pwedge q)vee (pwedge r) to (q vee r)$



I tried to solve it with this:




  1. (p⋀q)⋁(p⋀r) (premise)

  2. (p⋀q) (Assumption)

  3. p (⋀-elimination)

  4. p⋀r (Assumption)

  5. p (⋀-elimination)

  6. p (⋁-elimination 3,5)


But this seems wrong. Does anyone else have a clue on which rules to apply for this? Thank you.










share|cite|improve this question











$endgroup$




Only using rules of inferences to prove that $(pwedge q)vee (pwedge r) to (q vee r)$



I tried to solve it with this:




  1. (p⋀q)⋁(p⋀r) (premise)

  2. (p⋀q) (Assumption)

  3. p (⋀-elimination)

  4. p⋀r (Assumption)

  5. p (⋀-elimination)

  6. p (⋁-elimination 3,5)


But this seems wrong. Does anyone else have a clue on which rules to apply for this? Thank you.







discrete-mathematics logic






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Feb 1 at 4:11







alice123019

















asked Feb 1 at 3:36









alice123019alice123019

84




84








  • 1




    $begingroup$
    What rules of inference are you allowed to use? Impossible to answer without knowing this.
    $endgroup$
    – David
    Feb 1 at 3:42












  • $begingroup$
    Introduction rules and elimination rules
    $endgroup$
    – alice123019
    Feb 1 at 3:50










  • $begingroup$
    What have you tried? It is a fairly easy proof, so where are you having trouble?
    $endgroup$
    – Graham Kemp
    Feb 1 at 3:52










  • $begingroup$
    Do you have the distributive law?
    $endgroup$
    – vadim123
    Feb 1 at 4:10










  • $begingroup$
    Distributive law is not allowed to use in this question
    $endgroup$
    – alice123019
    Feb 1 at 4:12














  • 1




    $begingroup$
    What rules of inference are you allowed to use? Impossible to answer without knowing this.
    $endgroup$
    – David
    Feb 1 at 3:42












  • $begingroup$
    Introduction rules and elimination rules
    $endgroup$
    – alice123019
    Feb 1 at 3:50










  • $begingroup$
    What have you tried? It is a fairly easy proof, so where are you having trouble?
    $endgroup$
    – Graham Kemp
    Feb 1 at 3:52










  • $begingroup$
    Do you have the distributive law?
    $endgroup$
    – vadim123
    Feb 1 at 4:10










  • $begingroup$
    Distributive law is not allowed to use in this question
    $endgroup$
    – alice123019
    Feb 1 at 4:12








1




1




$begingroup$
What rules of inference are you allowed to use? Impossible to answer without knowing this.
$endgroup$
– David
Feb 1 at 3:42






$begingroup$
What rules of inference are you allowed to use? Impossible to answer without knowing this.
$endgroup$
– David
Feb 1 at 3:42














$begingroup$
Introduction rules and elimination rules
$endgroup$
– alice123019
Feb 1 at 3:50




$begingroup$
Introduction rules and elimination rules
$endgroup$
– alice123019
Feb 1 at 3:50












$begingroup$
What have you tried? It is a fairly easy proof, so where are you having trouble?
$endgroup$
– Graham Kemp
Feb 1 at 3:52




$begingroup$
What have you tried? It is a fairly easy proof, so where are you having trouble?
$endgroup$
– Graham Kemp
Feb 1 at 3:52












$begingroup$
Do you have the distributive law?
$endgroup$
– vadim123
Feb 1 at 4:10




$begingroup$
Do you have the distributive law?
$endgroup$
– vadim123
Feb 1 at 4:10












$begingroup$
Distributive law is not allowed to use in this question
$endgroup$
– alice123019
Feb 1 at 4:12




$begingroup$
Distributive law is not allowed to use in this question
$endgroup$
– alice123019
Feb 1 at 4:12










1 Answer
1






active

oldest

votes


















0












$begingroup$

$deffitch#1#2{quadbegin{array}{|l}#1\hline #2end{array}}$




I tried to solve it with this:




  1. (p⋀q)⋁(p⋀r) → (q⋁r) (premise)

  2. (p⋀q) (Assumption)

  3. p (⋀-elimination)

  4. p⋀r (Assumption)

  5. p (⋀-elimination)




Don't ever start by premising what you seek to prove.   This is a proof with no premises.



Since you want to introduce a conditional, use a conditional proof -- assume the antecedant in order to derive the consequent.



Since that assumption is a disjunction, eliminate it with a proof by cases. In each case assume the left or right of the disjunction and aim to derive the consequent.



Since each case is a conjunction, eliminate it to the part that enables you to derive the consequent by introducing a disjunction.



Finish by introducing the conditional and you are done.



Fill in the dots.



$$fitch{}{fitch{ldots}{fitch{ldots}{ldots\ldots}\fitch{ldots}{ldots\ldots}\ldots}\((pland q)lor(pland r))to(qlor r)}$$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Gotcha! Thanks for the great explanation.
    $endgroup$
    – alice123019
    Feb 1 at 4:29












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1 Answer
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active

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1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









0












$begingroup$

$deffitch#1#2{quadbegin{array}{|l}#1\hline #2end{array}}$




I tried to solve it with this:




  1. (p⋀q)⋁(p⋀r) → (q⋁r) (premise)

  2. (p⋀q) (Assumption)

  3. p (⋀-elimination)

  4. p⋀r (Assumption)

  5. p (⋀-elimination)




Don't ever start by premising what you seek to prove.   This is a proof with no premises.



Since you want to introduce a conditional, use a conditional proof -- assume the antecedant in order to derive the consequent.



Since that assumption is a disjunction, eliminate it with a proof by cases. In each case assume the left or right of the disjunction and aim to derive the consequent.



Since each case is a conjunction, eliminate it to the part that enables you to derive the consequent by introducing a disjunction.



Finish by introducing the conditional and you are done.



Fill in the dots.



$$fitch{}{fitch{ldots}{fitch{ldots}{ldots\ldots}\fitch{ldots}{ldots\ldots}\ldots}\((pland q)lor(pland r))to(qlor r)}$$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Gotcha! Thanks for the great explanation.
    $endgroup$
    – alice123019
    Feb 1 at 4:29
















0












$begingroup$

$deffitch#1#2{quadbegin{array}{|l}#1\hline #2end{array}}$




I tried to solve it with this:




  1. (p⋀q)⋁(p⋀r) → (q⋁r) (premise)

  2. (p⋀q) (Assumption)

  3. p (⋀-elimination)

  4. p⋀r (Assumption)

  5. p (⋀-elimination)




Don't ever start by premising what you seek to prove.   This is a proof with no premises.



Since you want to introduce a conditional, use a conditional proof -- assume the antecedant in order to derive the consequent.



Since that assumption is a disjunction, eliminate it with a proof by cases. In each case assume the left or right of the disjunction and aim to derive the consequent.



Since each case is a conjunction, eliminate it to the part that enables you to derive the consequent by introducing a disjunction.



Finish by introducing the conditional and you are done.



Fill in the dots.



$$fitch{}{fitch{ldots}{fitch{ldots}{ldots\ldots}\fitch{ldots}{ldots\ldots}\ldots}\((pland q)lor(pland r))to(qlor r)}$$






share|cite|improve this answer









$endgroup$













  • $begingroup$
    Gotcha! Thanks for the great explanation.
    $endgroup$
    – alice123019
    Feb 1 at 4:29














0












0








0





$begingroup$

$deffitch#1#2{quadbegin{array}{|l}#1\hline #2end{array}}$




I tried to solve it with this:




  1. (p⋀q)⋁(p⋀r) → (q⋁r) (premise)

  2. (p⋀q) (Assumption)

  3. p (⋀-elimination)

  4. p⋀r (Assumption)

  5. p (⋀-elimination)




Don't ever start by premising what you seek to prove.   This is a proof with no premises.



Since you want to introduce a conditional, use a conditional proof -- assume the antecedant in order to derive the consequent.



Since that assumption is a disjunction, eliminate it with a proof by cases. In each case assume the left or right of the disjunction and aim to derive the consequent.



Since each case is a conjunction, eliminate it to the part that enables you to derive the consequent by introducing a disjunction.



Finish by introducing the conditional and you are done.



Fill in the dots.



$$fitch{}{fitch{ldots}{fitch{ldots}{ldots\ldots}\fitch{ldots}{ldots\ldots}\ldots}\((pland q)lor(pland r))to(qlor r)}$$






share|cite|improve this answer









$endgroup$



$deffitch#1#2{quadbegin{array}{|l}#1\hline #2end{array}}$




I tried to solve it with this:




  1. (p⋀q)⋁(p⋀r) → (q⋁r) (premise)

  2. (p⋀q) (Assumption)

  3. p (⋀-elimination)

  4. p⋀r (Assumption)

  5. p (⋀-elimination)




Don't ever start by premising what you seek to prove.   This is a proof with no premises.



Since you want to introduce a conditional, use a conditional proof -- assume the antecedant in order to derive the consequent.



Since that assumption is a disjunction, eliminate it with a proof by cases. In each case assume the left or right of the disjunction and aim to derive the consequent.



Since each case is a conjunction, eliminate it to the part that enables you to derive the consequent by introducing a disjunction.



Finish by introducing the conditional and you are done.



Fill in the dots.



$$fitch{}{fitch{ldots}{fitch{ldots}{ldots\ldots}\fitch{ldots}{ldots\ldots}\ldots}\((pland q)lor(pland r))to(qlor r)}$$







share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Feb 1 at 4:17









Graham KempGraham Kemp

87.8k43578




87.8k43578












  • $begingroup$
    Gotcha! Thanks for the great explanation.
    $endgroup$
    – alice123019
    Feb 1 at 4:29


















  • $begingroup$
    Gotcha! Thanks for the great explanation.
    $endgroup$
    – alice123019
    Feb 1 at 4:29
















$begingroup$
Gotcha! Thanks for the great explanation.
$endgroup$
– alice123019
Feb 1 at 4:29




$begingroup$
Gotcha! Thanks for the great explanation.
$endgroup$
– alice123019
Feb 1 at 4:29


















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