Equivalence Relations on the Set of Integers - Homework Solution

Click For Summary
SUMMARY

The discussion centers on determining whether the relation defined by \( aRb \) if \( ab \geq 0 \) is an equivalence relation on the set of integers \( S \). The three properties required for equivalence relations—reflexivity, symmetry, and transitivity—are examined. Reflexivity is satisfied since \( aRa \) holds true for all integers \( a \) (as \( a \cdot a \geq 0 \)). Symmetry is also confirmed, as \( aRb \) implies \( bRa \) due to the commutative property of multiplication. Lastly, transitivity is established since if \( aRb \) and \( bRc \), then \( aRc \) follows from the non-negativity of the products.

PREREQUISITES
  • Understanding of equivalence relations in mathematics
  • Basic knowledge of integer properties
  • Familiarity with reflexivity, symmetry, and transitivity concepts
  • Ability to manipulate and analyze inequalities
NEXT STEPS
  • Study the properties of equivalence relations in more depth
  • Explore examples of equivalence relations on different sets
  • Learn about the implications of equivalence classes
  • Investigate other mathematical relations and their classifications
USEFUL FOR

Students studying abstract algebra, mathematics educators, and anyone interested in understanding equivalence relations and their applications in set theory.

eiselea
Messages
2
Reaction score
0

Homework Statement



Let S be the set of integers. If a,b\in S, define aRb if ab\geq0. Is R an equivalence relation on S?

Homework Equations





The Attempt at a Solution



Def: aRb=bRa \rightarrow ab=ba
assume that aRb and bRc \Rightarrow aRc
a=b and b=c
since a=b, the substitute a in for b to get a=c


I don't know where to go from here.
 
Physics news on Phys.org
You must check 3 things:

1) That aRa (reflexivity)
2) That aRb implies bRa (symetry)
3) That aRb and bRc implies aRc (transitivity)
 
So what I have done so far answers the first part of the question?
 
But you haven't explained anything.

1) Why does aRa for every integer a??
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
1K
  • · Replies 3 ·
Replies
3
Views
12K
  • · Replies 2 ·
Replies
2
Views
4K
Replies
2
Views
8K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K