Proving C(S,F) is a Subspace of F(S,F)

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Discussion Overview

The discussion revolves around proving that the set C(S,F) is a subspace of F(S,F), where S is a nonempty set and F is a field. The focus is on the properties of functions in C(S,F) and their relationship to the zero vector in the context of vector spaces.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant asserts that the zero function cannot be considered a member of C(S,F) because it is not nonzero at any finite number of points in S.
  • Another participant suggests that being zero for all elements of S could be interpreted as being zero for all but finitely many elements of S.
  • A different participant questions whether it is possible for the zero vector to exist if the function must be nonzero at a couple of points.
  • One participant concludes that if the function must be nonzero at some points, then a "0" vector cannot exist in C(S,F).

Areas of Agreement / Disagreement

Participants express disagreement regarding the definition of the zero vector in the context of C(S,F) and whether the zero function qualifies under the given conditions.

Contextual Notes

The discussion highlights ambiguities related to the definitions of S and the nature of functions in C(S,F), particularly concerning the finite nonzero points and the implications for the zero vector.

Riemannliness
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Here's one I've been stewing over:
- Let S be a nonempty set of F, and F a field.
- Let F(S,F) be the set of all functions from S to the field F.
- Let C(S,F) denote the set of all functions f [tex]\in[/tex] F(S,F), such that f(s) = 0 for all but a finite number of elements in S (s [tex]\in[/tex] S).
Prove that C(S,F) is a subspace of F(S,F).

It's simple to show that the space is closed under addition and scalar multiplication, but I'm having a hard time finding a zero. It certainly isn't the zero function because that function is not nonzero at any finite number of points in S. I've played with a few ideas, but it always comes down to the ambiguity of the definition of S and the specifics of the finite nonzero points mapped by the functions. I can find functions that work for each specific case, but not one that works in all cases. I feel like I'm missing something relatively simple, so hints (BUT NOT ANSWERS) would be appreciated :biggrin:.
 
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Being 0 for all elements of S probably counts as being 0 for all but finitely many elements of S
 
You're probably right. But I was under the impression that it had to be nonzero at least a couple points. Would it be possible if that were the case?
 
Obviously not, since in that case you would not have a "0" vector.
 

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