Does Rearranging Quantifiers Affect Looping in Nested Statements?

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In summary, the conversation is discussing the use of quantifiers to express a statement about students and faculty members in a school. It is noted that bringing all the quantifiers to the front may not make a difference in this case, but it could make expressions harder to read.
  • #1
SamitC
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Hello,
Suppose a problem statement is :

In a school, suppose S(x) is “x is a student”, F(x) is “x is a faculty member” and A (x, y) is “x asked a question to y”. Domain is all the people associated with the school. Write the following using quantifiers:
"Some student did not ask any faculty member a question".

Answers are:

So, ∃x [S(x) ∧ ∀y {F(y) → ¬ A(x, y)}] OR ∃x [S(x) ∧ ¬∃y {F(y)A(x, y)}]

Instead, if we bring all the quantifiers at the front, will it cause any difference? Like:
xy [S(x) ∧ {F(y) → ¬ A(x, y)}] OR ∃x ¬∃y [S(x) ∧ {F(y)A(x, y)}]

In general, does it ever cause any change in looping if we bring all quantifiers at the front? Or is there any specific reason not to put all quantifiers at the front?

Thanks
 
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  • #2
In this case it doesn't make a difference, but sometimes it can make the expressions harder to read because you have to remember all the variables and their quantifiers before they are actually used.

There could be expressions where it makes a difference, although I don't have an example right now.
 
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  • #3
mfb said:
In this case it doesn't make a difference, but sometimes it can make the expressions harder to read because you have to remember all the variables and their quantifiers before they are actually used.

There could be expressions where it makes a difference, although I don't have an example right now.
Thank you.
 

Related to Does Rearranging Quantifiers Affect Looping in Nested Statements?

What is a nested quantifier question?

A nested quantifier question is a type of mathematical or logical question that involves multiple quantifiers, which are symbols used to indicate the scope or extent of a statement. In a nested quantifier question, these quantifiers are used in a hierarchical or nested structure, with one quantifier being contained within the scope of another.

What is an example of a nested quantifier question?

An example of a nested quantifier question is: "For all x, there exists y such that x is greater than y." In this question, the quantifier "for all" is nested within the quantifier "there exists," indicating that the statement applies to all possible values of x and y.

Why are nested quantifier questions important?

Nested quantifier questions are important because they allow us to make precise and complex statements about relationships between variables or objects. They are commonly used in mathematical and logical proofs, as well as in computer science and other fields that involve formal reasoning.

What are some common mistakes made when dealing with nested quantifier questions?

Some common mistakes made when dealing with nested quantifier questions include misinterpreting the order or scope of quantifiers, failing to use parentheses or other symbols to indicate nested structures, and incorrectly assuming that a statement is true or false based on the placement of quantifiers.

How can I improve my understanding of nested quantifier questions?

To improve your understanding of nested quantifier questions, it is helpful to practice writing out statements using quantifiers and identifying their scope and relationships. It may also be helpful to study formal logic and mathematical proofs, as well as working through examples and exercises provided by textbooks or online resources.

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