Bezout Identity: Is r∈S U {0} Necessary to Prove?

  • Context: Undergrad 
  • Thread starter Thread starter Suyogya
  • Start date Start date
  • Tags Tags
    Identity
Click For Summary

Discussion Overview

The discussion focuses on the necessity of showing that a value \( r \) belongs to the set \( S \cup \{0\} \) in the context of proving Bézout's identity. Participants explore the implications of this condition on the proof's validity, particularly regarding the minimality of certain elements.

Discussion Character

  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants question the necessity of showing that \( r \) belongs to \( S \cup \{0\} \), arguing that if \( r \) is zero, its membership in the set does not affect the proof.
  • Others assert that if \( r \notin S \cup \{0\} \), the minimality of another element \( d \) becomes irrelevant to \( r \), and thus one cannot conclude \( r = 0 \).
  • A participant proposes that the need to show \( r \in S \cup \{0\} \) may be related to comparing \( r \) with \( d \), questioning whether only elements from the same set can be compared.
  • Another participant elaborates on the comparison of elements, suggesting that if \( d \) is minimal in \( S \) and \( r \) is in \( S \cup \{0\} \), then either \( r = 0 \) or \( d \leq r \) must hold, emphasizing the importance of \( r \)'s membership in the set for the argument to hold.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of \( r \) belonging to \( S \cup \{0\} \) for the proof of Bézout's identity. No consensus is reached, as multiple competing perspectives remain regarding the implications of this condition.

Contextual Notes

The discussion highlights the dependence on definitions and the implications of minimality in set comparisons, which remain unresolved within the context of the proof.

Suyogya
Messages
14
Reaction score
0
Mathematics news on Phys.org
Suyogya said:
what is the need to show that r belongs to S U {0} in proof (https://en.wikipedia.org/wiki/Bézout's_identity#Proof)

r is zero afterall, whether it lies in S U {0} or not doesn't affect.
If ##r \notin S\cup \{\,0\,\}##, then the minimality of ##d## has nothing to do with ##r## and we cannot conclude ##r=0##. It is zero, because it is part of this set!
 
fresh_42 said:
If ##r \notin S\cup \{\,0\,\}##, then the minimality of ##d## has nothing to do with ##r## and we cannot conclude ##r=0##. It is zero, because it is part of this set!
please tell the following:
is the need to show that r lies in S U {0} just because to compare r is less than or equal to d (as d also belongs to S U {0})?
So are only the same set elements can be compared? If yes, then consider a counter example, set a={10}, set b={5} couldn't we say 5<10 (as both belongs to different sets).
 
Last edited:
Suyogya said:
please tell the following:
is the need to show that r lies in S U {0} just because to compare r is less than or equal to d (as d also belongs to S U {0})?
So are only the same set elements can be compared? If yes, then consider a counter example, set a={10}, set b={5} couldn't we say 5<10 (as both belongs to different sets).
We start with a set ##M##. Then we choose a minimal element of ##M##, called ##m##. In order to compare any other element ##n## to ##m##, we can only do this, if ##n \in M##, because then we know, that ##m \leq n## as ##m## was chosen minimal. Otherwise we can't say anything.

If in our example, ##d \in S## is minimal, and ##r if \in S \cup \{\,0\,\}##, then either ##r=0## or ##d \leq r##. As ##r < d##, the second is impossible, leaving ##r=0## as only possibility. This entire argument needs ##r if \in S \cup \{\,0\,\}## and that ##d\in S## is the smallest integer there.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 5 ·
Replies
5
Views
4K
  • · Replies 4 ·
Replies
4
Views
3K
Replies
8
Views
5K
  • · Replies 16 ·
Replies
16
Views
5K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 0 ·
Replies
0
Views
2K