Using inference to prove that $(pwedge q)vee (pwedge r) to (q vee r)$.
$begingroup$
Only using rules of inferences to prove that $(pwedge q)vee (pwedge r) to (q vee r)$
I tried to solve it with this:
- (p⋀q)⋁(p⋀r) (premise)
- (p⋀q) (Assumption)
- p (⋀-elimination)
- p⋀r (Assumption)
- p (⋀-elimination)
- 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
$endgroup$
add a comment |
$begingroup$
Only using rules of inferences to prove that $(pwedge q)vee (pwedge r) to (q vee r)$
I tried to solve it with this:
- (p⋀q)⋁(p⋀r) (premise)
- (p⋀q) (Assumption)
- p (⋀-elimination)
- p⋀r (Assumption)
- p (⋀-elimination)
- 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
$endgroup$
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
add a comment |
$begingroup$
Only using rules of inferences to prove that $(pwedge q)vee (pwedge r) to (q vee r)$
I tried to solve it with this:
- (p⋀q)⋁(p⋀r) (premise)
- (p⋀q) (Assumption)
- p (⋀-elimination)
- p⋀r (Assumption)
- p (⋀-elimination)
- 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
$endgroup$
Only using rules of inferences to prove that $(pwedge q)vee (pwedge r) to (q vee r)$
I tried to solve it with this:
- (p⋀q)⋁(p⋀r) (premise)
- (p⋀q) (Assumption)
- p (⋀-elimination)
- p⋀r (Assumption)
- p (⋀-elimination)
- 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
discrete-mathematics logic
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
add a comment |
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
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
$deffitch#1#2{quadbegin{array}{|l}#1\hline #2end{array}}$
I tried to solve it with this:
- (p⋀q)⋁(p⋀r) → (q⋁r) (premise)
- (p⋀q) (Assumption)
- p (⋀-elimination)
- p⋀r (Assumption)
- 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)}$$
$endgroup$
$begingroup$
Gotcha! Thanks for the great explanation.
$endgroup$
– alice123019
Feb 1 at 4:29
add a comment |
Your Answer
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1 Answer
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votes
$begingroup$
$deffitch#1#2{quadbegin{array}{|l}#1\hline #2end{array}}$
I tried to solve it with this:
- (p⋀q)⋁(p⋀r) → (q⋁r) (premise)
- (p⋀q) (Assumption)
- p (⋀-elimination)
- p⋀r (Assumption)
- p (⋀-elimination)
Don't ever start by premising what you seek to prove. This is a proof with no premises.
Since you want to introduce a conditional, use a conditional proof -- assume the antecedant in order to derive the consequent.
Since that assumption is a disjunction, eliminate it with a proof by cases. In each case assume the left or right of the disjunction and aim to derive the consequent.
Since each case is a conjunction, eliminate it to the part that enables you to derive the consequent by introducing a disjunction.
Finish by introducing the conditional and you are done.
Fill in the dots.
$$fitch{}{fitch{ldots}{fitch{ldots}{ldots\ldots}\fitch{ldots}{ldots\ldots}\ldots}\((pland q)lor(pland r))to(qlor r)}$$
$endgroup$
$begingroup$
Gotcha! Thanks for the great explanation.
$endgroup$
– alice123019
Feb 1 at 4:29
add a comment |
$begingroup$
$deffitch#1#2{quadbegin{array}{|l}#1\hline #2end{array}}$
I tried to solve it with this:
- (p⋀q)⋁(p⋀r) → (q⋁r) (premise)
- (p⋀q) (Assumption)
- p (⋀-elimination)
- p⋀r (Assumption)
- p (⋀-elimination)
Don't ever start by premising what you seek to prove. This is a proof with no premises.
Since you want to introduce a conditional, use a conditional proof -- assume the antecedant in order to derive the consequent.
Since that assumption is a disjunction, eliminate it with a proof by cases. In each case assume the left or right of the disjunction and aim to derive the consequent.
Since each case is a conjunction, eliminate it to the part that enables you to derive the consequent by introducing a disjunction.
Finish by introducing the conditional and you are done.
Fill in the dots.
$$fitch{}{fitch{ldots}{fitch{ldots}{ldots\ldots}\fitch{ldots}{ldots\ldots}\ldots}\((pland q)lor(pland r))to(qlor r)}$$
$endgroup$
$begingroup$
Gotcha! Thanks for the great explanation.
$endgroup$
– alice123019
Feb 1 at 4:29
add a comment |
$begingroup$
$deffitch#1#2{quadbegin{array}{|l}#1\hline #2end{array}}$
I tried to solve it with this:
- (p⋀q)⋁(p⋀r) → (q⋁r) (premise)
- (p⋀q) (Assumption)
- p (⋀-elimination)
- p⋀r (Assumption)
- p (⋀-elimination)
Don't ever start by premising what you seek to prove. This is a proof with no premises.
Since you want to introduce a conditional, use a conditional proof -- assume the antecedant in order to derive the consequent.
Since that assumption is a disjunction, eliminate it with a proof by cases. In each case assume the left or right of the disjunction and aim to derive the consequent.
Since each case is a conjunction, eliminate it to the part that enables you to derive the consequent by introducing a disjunction.
Finish by introducing the conditional and you are done.
Fill in the dots.
$$fitch{}{fitch{ldots}{fitch{ldots}{ldots\ldots}\fitch{ldots}{ldots\ldots}\ldots}\((pland q)lor(pland r))to(qlor r)}$$
$endgroup$
$deffitch#1#2{quadbegin{array}{|l}#1\hline #2end{array}}$
I tried to solve it with this:
- (p⋀q)⋁(p⋀r) → (q⋁r) (premise)
- (p⋀q) (Assumption)
- p (⋀-elimination)
- p⋀r (Assumption)
- p (⋀-elimination)
Don't ever start by premising what you seek to prove. This is a proof with no premises.
Since you want to introduce a conditional, use a conditional proof -- assume the antecedant in order to derive the consequent.
Since that assumption is a disjunction, eliminate it with a proof by cases. In each case assume the left or right of the disjunction and aim to derive the consequent.
Since each case is a conjunction, eliminate it to the part that enables you to derive the consequent by introducing a disjunction.
Finish by introducing the conditional and you are done.
Fill in the dots.
$$fitch{}{fitch{ldots}{fitch{ldots}{ldots\ldots}\fitch{ldots}{ldots\ldots}\ldots}\((pland q)lor(pland r))to(qlor r)}$$
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
add a comment |
$begingroup$
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
add a comment |
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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