Are All Math Definitions 'If and Only If' Statements?

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Discussion Overview

The discussion revolves around whether all mathematical definitions should be interpreted as 'if and only if' statements. Participants explore the implications of defining terms in mathematics and the potential consequences of not adhering to this standard.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant questions whether definitions in mathematics should always be interpreted as 'if and only if' statements, citing an example where a definition is presented as A => B.
  • Another participant argues that a definition like "A field is a Galois field if it is of finite cardinality" implies a stronger relationship, suggesting that it should be understood as an equivalence rather than a one-way implication.
  • Some participants express a belief that definitions inherently assert equivalence, noting that omitting the "only if" part can lead to misunderstandings.
  • A participant humorously acknowledges their own tendency to overlook the "only if" aspect in definitions, suggesting a shared experience among others.
  • There is a call for those who disagree with the 'if and only if' interpretation to provide their reasoning.

Areas of Agreement / Disagreement

Participants express differing views on whether all definitions should be seen as 'if and only if' statements, indicating that the discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Some assumptions about the nature of definitions in mathematics and their interpretations are not fully articulated, leaving room for further exploration of the topic.

All definitions are 'if and only if' statements?

  • Yes

    Votes: 10 71.4%
  • No

    Votes: 4 28.6%

  • Total voters
    14
pivoxa15
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Are all definitions in maths 'if and only if' statement?

One book actaully has A=>B as a definition but I should intepret it as A<=>B as the definition?
 
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Think about it for a second. ;)

For instance, if by "A field is a Galois field if it is of finite cardinality" me meant only that "finite cardinality ==> it's Galois", then it would be without meaning to say that a field is Galois. But our goal is precisely to be able to say "a Galois field" instead of the words "a field of finite cardinality", because it's shorter.
 
Last edited:
oy vei... (-:
 
Yes, every definition says "this" and "that" are the same and so is always an "if and only if" statement. Sometimes people get lazy and don't include the "only if" part, but they should! (I've been guilty of that myself, but I'm notoriously lazy! Often I sit at the computer answering silly questions when I should be workin.)
 
HallsofIvy said:
(I've been guilty of that myself, but I'm notoriously lazy! Often I sit at the computer answering silly questions when I should be workin.)

Greg doesn't pay enough for the mentorring, well you can go on a strike like the israeli lecturers it won't get you far though.
(-:
 
For those who voted no, state your reason.
 

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