What is the notation for the statement for some integer n ?

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Discussion Overview

The discussion revolves around the notation used to express the statement "for some integer n." Participants explore various mathematical notations and their meanings, focusing on the correct symbols to convey existence in the context of integers and rational numbers.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether the notation \forall n | n \in Z represents "for all integers n" or if another notation is more appropriate.
  • Another participant suggests that the notation indicating existence is represented by a symbol resembling a backwards capital E, which signifies "there exists." They provide an example involving the square root of 9.
  • There is a request for clarification on the symbol for "such that."
  • One participant confirms their interpretation of the notations, explaining \forall n | n \in Z and \{n | n \in Z\} in their own words.
  • A participant shares a notation \exists n \in Q s.t. n \in Z, indicating existence but acknowledges it as a trivial statement.
  • There is a question about the phrasing "there exists n a rational" and a suggestion for better grammar, leading to a clarification that it should be "there exist a rational number n such that n is an integer."
  • Another participant expresses gratitude for the clarification on grammar.

Areas of Agreement / Disagreement

Participants express differing interpretations of mathematical notation, particularly regarding the symbols for existence and the meaning of the vertical bar. There is no consensus on a single notation for "for some integer n," as various interpretations and preferences are presented.

Contextual Notes

Some participants express uncertainty about the correct use of symbols and grammar in mathematical statements, indicating a need for clarity in notation.

Nothing000
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What is the notation for the statement "for some integer n"?

What is the notation for the statement "for some integer n"?
Is it [tex]\forall n | n \in Z[/tex]
Or is it [tex]\{n | n \in Z \}[/tex]

Or is it something else?

[tex]|[/tex] does mean "such that", doesn't it?
 
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The first notation you show means for all integers n. The second is the set of all integers. What you're looking for, I think, is notation that indicates there exists at least one n that the statement is true for. I don't know how to make the symbol in latex, but it looks like a backwards capital E. Pretending my E is actually backwards for the purposes of this:

Example:

E n s.t.[tex]\sqrt{9} = n[/tex]

could be read as there exists n such that the square root of 9 equals n. Alternatively, you could say the square root of 9 equals n for some n
 
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What is the symbol for "such that"?
 
Tell me if I am interpreting my first two notations correctly.
I would read [tex]\forall n | n \in Z[/tex] as "for all n such that n is an element of the set of integers".

And I would read [tex]\{n | n \in Z \}[/tex] as "the set of n such that n is an element of the set of integers".
 
First, I found how to do the symbol:

[tex]\exists n \in Q s.t. n \in Z[/tex]

reads there exists n a rational such that n is an integer (a trivial statement, I admit :) ).

generally, the vertical bar is only used in your second example, for your first example it would be better to put s.t. (for such that).
 
Office_Shredder said:
[tex]\exists n \in Q s.t. n \in Z[/tex]

reads there exists n a rational such that n is an integer

What do you mean "there exists n a rational"?
 
Off the topic, but do you know what the RMS voltage is of a triangle wave?
 
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Nothing000 said:
What do you mean "there exists n a rational"?
Better grammar: there exist a rationa number n such that n is an integer.
 
HallsofIvy said:
Better grammar: there exist a rationa number n such that n is an integer.

That makes more sense. Thanks.
 

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