Why Use a - b Instead of a + b in Equivalence Classes of Rings?

Click For Summary

Discussion Overview

The discussion revolves around the use of the expression a - b in the context of equivalence classes of rings, specifically questioning why this form is preferred over a + b. The scope includes theoretical aspects of ring theory and equivalence relations.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant expresses confusion regarding the definition involving a - b and questions why it is used instead of a + b.
  • Another participant asks for clarification on whether the goal is to prove that a - b is an equivalence relation.
  • A different participant argues that using a - b is natural because it leads to the conclusion that a - b = 0 when considering the quotient by I, which implies a = b.
  • Another point raised suggests that one would want a to be equivalent to itself, which is supported by the expression a - a in I, rather than a + a.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus, as there are differing views on the appropriateness of using a - b versus a + b in this context.

Contextual Notes

The discussion may involve assumptions about the properties of equivalence relations and the nature of the ideal I, which are not fully articulated.

InquilineKea
Messages
1
Reaction score
0
So I'm kind of confused about the definition:

a-b\in I

Why a - b instead of a + b?
 
Physics news on Phys.org
Are you trying to prove that a-b is an equivalence relation? Can you be more specific?
 
Last edited:
It's actually natural to write a-b because I becomes zero when you quotient out by it, so a-b in I means a-b=0 or, written differently, a=b.
 
you would presumably want a equivalent to a, which follows from a-a in I, rather than a+a in I.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 24 ·
Replies
24
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 55 ·
2
Replies
55
Views
8K
  • · Replies 21 ·
Replies
21
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K