âManyâ quantifier in first order logic [closed]
Clash Royale CLAN TAG#URR8PPP
up vote
-2
down vote
favorite
Suppose I want to express this sentence in first-order logic:
"Many printers are broken"
If $p(x)$ is true if the term $x$ is a printer and $b(x)$ is true if $x$ is broken, how can I express this sentence?
logic first-order-logic predicate-logic quantifiers logic-translation
closed as off-topic by Shaun, Adrian Keister, Leucippus, user99914, Xander Henderson Sep 11 at 1:44
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." â Shaun, Adrian Keister, Leucippus, Community, Xander Henderson
add a comment |Â
up vote
-2
down vote
favorite
Suppose I want to express this sentence in first-order logic:
"Many printers are broken"
If $p(x)$ is true if the term $x$ is a printer and $b(x)$ is true if $x$ is broken, how can I express this sentence?
logic first-order-logic predicate-logic quantifiers logic-translation
closed as off-topic by Shaun, Adrian Keister, Leucippus, user99914, Xander Henderson Sep 11 at 1:44
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." â Shaun, Adrian Keister, Leucippus, Community, Xander Henderson
1
You cannot; you can see Generalized quantifiers : see e.g. $text most_M (A,B)$ ("most $A$ are $B$").
â Mauro ALLEGRANZA
Sep 10 at 19:55
add a comment |Â
up vote
-2
down vote
favorite
up vote
-2
down vote
favorite
Suppose I want to express this sentence in first-order logic:
"Many printers are broken"
If $p(x)$ is true if the term $x$ is a printer and $b(x)$ is true if $x$ is broken, how can I express this sentence?
logic first-order-logic predicate-logic quantifiers logic-translation
Suppose I want to express this sentence in first-order logic:
"Many printers are broken"
If $p(x)$ is true if the term $x$ is a printer and $b(x)$ is true if $x$ is broken, how can I express this sentence?
logic first-order-logic predicate-logic quantifiers logic-translation
logic first-order-logic predicate-logic quantifiers logic-translation
edited Sep 11 at 13:14
Taroccoesbrocco
4,17461535
4,17461535
asked Sep 10 at 19:50
Koinos
757
757
closed as off-topic by Shaun, Adrian Keister, Leucippus, user99914, Xander Henderson Sep 11 at 1:44
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." â Shaun, Adrian Keister, Leucippus, Community, Xander Henderson
closed as off-topic by Shaun, Adrian Keister, Leucippus, user99914, Xander Henderson Sep 11 at 1:44
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." â Shaun, Adrian Keister, Leucippus, Community, Xander Henderson
1
You cannot; you can see Generalized quantifiers : see e.g. $text most_M (A,B)$ ("most $A$ are $B$").
â Mauro ALLEGRANZA
Sep 10 at 19:55
add a comment |Â
1
You cannot; you can see Generalized quantifiers : see e.g. $text most_M (A,B)$ ("most $A$ are $B$").
â Mauro ALLEGRANZA
Sep 10 at 19:55
1
1
You cannot; you can see Generalized quantifiers : see e.g. $text most_M (A,B)$ ("most $A$ are $B$").
â Mauro ALLEGRANZA
Sep 10 at 19:55
You cannot; you can see Generalized quantifiers : see e.g. $text most_M (A,B)$ ("most $A$ are $B$").
â Mauro ALLEGRANZA
Sep 10 at 19:55
add a comment |Â
1 Answer
1
active
oldest
votes
up vote
6
down vote
accepted
First-order logic does not have a notion of "many" - this, like "most," "almost all," etc. is an example of a generalized quantifier, and handling them takes us to extensions of first-order logic.
We can express each of the following in first-order logic:
"Some printer is broken." ($exists x(p(x)wedge b(x))$)
"Multiple printers are broken." ($exists x,y(xnot=y wedge p(x)wedge p(y)wedge b(x)wedge b(y))$)
"At least $n$ printers are broken." ($exists x_1,...,x_n((bigwedge_1le i<jle nx_inot=x_j)wedge (bigwedge_1le kle np(x_k)wedge b(x_k))$)
"All printers are broken." ($forall x(p(x)implies b(x))$)
Is the inequality between terms an extension of first order logic ?
â Koinos
Sep 11 at 9:58
@Koinos You mean "$not=$?" No - "$=$" is a logical symbol in first-order logic (this is actually historically contingent - early versions of first-order logic didn't always include $=$), and "$anot=b$" is understood as an abbreviation for "$neg(a=b)$ (similarly, "$exists x,y$" is an abbreviation for "$exists xexists y$," and etc.).
â Noah Schweber
Sep 11 at 14:17
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
6
down vote
accepted
First-order logic does not have a notion of "many" - this, like "most," "almost all," etc. is an example of a generalized quantifier, and handling them takes us to extensions of first-order logic.
We can express each of the following in first-order logic:
"Some printer is broken." ($exists x(p(x)wedge b(x))$)
"Multiple printers are broken." ($exists x,y(xnot=y wedge p(x)wedge p(y)wedge b(x)wedge b(y))$)
"At least $n$ printers are broken." ($exists x_1,...,x_n((bigwedge_1le i<jle nx_inot=x_j)wedge (bigwedge_1le kle np(x_k)wedge b(x_k))$)
"All printers are broken." ($forall x(p(x)implies b(x))$)
Is the inequality between terms an extension of first order logic ?
â Koinos
Sep 11 at 9:58
@Koinos You mean "$not=$?" No - "$=$" is a logical symbol in first-order logic (this is actually historically contingent - early versions of first-order logic didn't always include $=$), and "$anot=b$" is understood as an abbreviation for "$neg(a=b)$ (similarly, "$exists x,y$" is an abbreviation for "$exists xexists y$," and etc.).
â Noah Schweber
Sep 11 at 14:17
add a comment |Â
up vote
6
down vote
accepted
First-order logic does not have a notion of "many" - this, like "most," "almost all," etc. is an example of a generalized quantifier, and handling them takes us to extensions of first-order logic.
We can express each of the following in first-order logic:
"Some printer is broken." ($exists x(p(x)wedge b(x))$)
"Multiple printers are broken." ($exists x,y(xnot=y wedge p(x)wedge p(y)wedge b(x)wedge b(y))$)
"At least $n$ printers are broken." ($exists x_1,...,x_n((bigwedge_1le i<jle nx_inot=x_j)wedge (bigwedge_1le kle np(x_k)wedge b(x_k))$)
"All printers are broken." ($forall x(p(x)implies b(x))$)
Is the inequality between terms an extension of first order logic ?
â Koinos
Sep 11 at 9:58
@Koinos You mean "$not=$?" No - "$=$" is a logical symbol in first-order logic (this is actually historically contingent - early versions of first-order logic didn't always include $=$), and "$anot=b$" is understood as an abbreviation for "$neg(a=b)$ (similarly, "$exists x,y$" is an abbreviation for "$exists xexists y$," and etc.).
â Noah Schweber
Sep 11 at 14:17
add a comment |Â
up vote
6
down vote
accepted
up vote
6
down vote
accepted
First-order logic does not have a notion of "many" - this, like "most," "almost all," etc. is an example of a generalized quantifier, and handling them takes us to extensions of first-order logic.
We can express each of the following in first-order logic:
"Some printer is broken." ($exists x(p(x)wedge b(x))$)
"Multiple printers are broken." ($exists x,y(xnot=y wedge p(x)wedge p(y)wedge b(x)wedge b(y))$)
"At least $n$ printers are broken." ($exists x_1,...,x_n((bigwedge_1le i<jle nx_inot=x_j)wedge (bigwedge_1le kle np(x_k)wedge b(x_k))$)
"All printers are broken." ($forall x(p(x)implies b(x))$)
First-order logic does not have a notion of "many" - this, like "most," "almost all," etc. is an example of a generalized quantifier, and handling them takes us to extensions of first-order logic.
We can express each of the following in first-order logic:
"Some printer is broken." ($exists x(p(x)wedge b(x))$)
"Multiple printers are broken." ($exists x,y(xnot=y wedge p(x)wedge p(y)wedge b(x)wedge b(y))$)
"At least $n$ printers are broken." ($exists x_1,...,x_n((bigwedge_1le i<jle nx_inot=x_j)wedge (bigwedge_1le kle np(x_k)wedge b(x_k))$)
"All printers are broken." ($forall x(p(x)implies b(x))$)
answered Sep 10 at 19:55
Noah Schweber
113k9143267
113k9143267
Is the inequality between terms an extension of first order logic ?
â Koinos
Sep 11 at 9:58
@Koinos You mean "$not=$?" No - "$=$" is a logical symbol in first-order logic (this is actually historically contingent - early versions of first-order logic didn't always include $=$), and "$anot=b$" is understood as an abbreviation for "$neg(a=b)$ (similarly, "$exists x,y$" is an abbreviation for "$exists xexists y$," and etc.).
â Noah Schweber
Sep 11 at 14:17
add a comment |Â
Is the inequality between terms an extension of first order logic ?
â Koinos
Sep 11 at 9:58
@Koinos You mean "$not=$?" No - "$=$" is a logical symbol in first-order logic (this is actually historically contingent - early versions of first-order logic didn't always include $=$), and "$anot=b$" is understood as an abbreviation for "$neg(a=b)$ (similarly, "$exists x,y$" is an abbreviation for "$exists xexists y$," and etc.).
â Noah Schweber
Sep 11 at 14:17
Is the inequality between terms an extension of first order logic ?
â Koinos
Sep 11 at 9:58
Is the inequality between terms an extension of first order logic ?
â Koinos
Sep 11 at 9:58
@Koinos You mean "$not=$?" No - "$=$" is a logical symbol in first-order logic (this is actually historically contingent - early versions of first-order logic didn't always include $=$), and "$anot=b$" is understood as an abbreviation for "$neg(a=b)$ (similarly, "$exists x,y$" is an abbreviation for "$exists xexists y$," and etc.).
â Noah Schweber
Sep 11 at 14:17
@Koinos You mean "$not=$?" No - "$=$" is a logical symbol in first-order logic (this is actually historically contingent - early versions of first-order logic didn't always include $=$), and "$anot=b$" is understood as an abbreviation for "$neg(a=b)$ (similarly, "$exists x,y$" is an abbreviation for "$exists xexists y$," and etc.).
â Noah Schweber
Sep 11 at 14:17
add a comment |Â
1
You cannot; you can see Generalized quantifiers : see e.g. $text most_M (A,B)$ ("most $A$ are $B$").
â Mauro ALLEGRANZA
Sep 10 at 19:55