What is a complete set of representatives for an equivalence relation on a set?

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SUMMARY

A complete set of representatives for the equivalence relation defined by (x,y)R(u,v) if and only if x² + y² = u² + v² consists of points on circles centered at the origin in the Cartesian plane. Each equivalence class corresponds to a unique radius, representing all points that lie on a specific circle. The solution requires identifying one point from each circle, which can be achieved by selecting points along the positive x-axis for each radius. This approach effectively demonstrates the relationship between the equivalence classes and the geometric interpretation of circles.

PREREQUISITES
  • Understanding of equivalence relations in set theory
  • Familiarity with Cartesian coordinates and geometric representations
  • Knowledge of basic algebraic concepts, particularly quadratic equations
  • Ability to visualize and interpret geometric shapes, specifically circles
NEXT STEPS
  • Explore the properties of equivalence relations in set theory
  • Study the geometric interpretation of functions and relations in the Cartesian plane
  • Learn about the implications of equivalence classes in mathematical proofs
  • Investigate the application of circles in various mathematical contexts, such as trigonometry
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Students studying abstract algebra, mathematicians interested in set theory, and educators teaching concepts related to equivalence relations and geometric interpretations.

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Homework Statement



Definition: let R be an equivalence relation on a set X. A subset of X containing exactly one element from each equivalence class is called a complete set of representatives. now define a relation R on RxR by (x,y)R(u,v) <---> x^2 + y^2 = u^2 + v^2. You don't have to prove that R is an equivalence relation. Find a complete set of representatives. Carefully justify the answer.

Homework Equations



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The Attempt at a Solution



I am not sure where to go with this. I know that x^2+y^2 is a circle. I am working with a few other people and this is all we could come up with!
 
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Evidently (x,y)R(u,v) iff (x,y) and (u,v) lie on the same circle centered at the origin. So this tells you precisely what the equivalence classes are.
 

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