Describe the partition for the equivalence relation T

Click For Summary

Homework Help Overview

The discussion revolves around determining whether a given collection of subsets constitutes a partition of a set A = {1,2,3,4,5,6,7}, as well as exploring the equivalence relation T defined for real numbers based on their greatest integer values.

Discussion Character

  • Conceptual clarification, Problem interpretation, Assumption checking

Approaches and Questions Raised

  • Participants discuss the definition of a partition and check if the subsets in script A satisfy this definition. Questions are raised about the nature of equivalence classes under the relation T and how to visualize them.

Discussion Status

Some participants have provided definitions and criteria for partitions and equivalence classes, while others are exploring examples to clarify their understanding. There is an ongoing exploration of whether the subsets cover all elements of A without overlap.

Contextual Notes

Participants are considering the implications of the definitions and the specific elements involved in the sets and equivalence relation. There is a focus on ensuring that all members of A are accounted for in the proposed partition.

needhelp83
Messages
193
Reaction score
0
For the set A = {1,2,3,4,5,6,7}, determine whether script A is a partition of A. script A = {{1,3,},{5,6}, {2,4},{7}}

Describe the partition for the equivalence relation T defined for x,y \in \mathbbc{R} by X T y iff \left[ \left[x \right] \right] = \left[ \left[y \right] \right] where \left[ \left[x \right] \right] is definied to be the greatest integer iin x (the largest integer n such that n \leq x).

Can anyone help me with this partition stuff. It would be very appreciated. :)
 
Physics news on Phys.org


Can you start by giving the definition of a partition?
Then try to check if the given sets A, \mathcal{A} satisfy this definition.

For the second one, can you imagine what the equivalence classes look like?
 


(i) If X \in \mathcal{A}, then X \neq \o
(ii) If X \in \mathcal{A} and Y \in \mathcal{A}, then X=Y or X \cap Y= \o
(iii)\bigcup_{X \in \mathal{A}}X=A

I found this to be a definition for an equivalence class:
In mathematics, given a set X and an equivalence relation ~ on X, the equivalence class of an element a in X is the subset of all elements in X which are equivalent to a:

\left[a\right]={x \in X|x \sim a}
 


needhelp83 said:
(i) If X \in \mathcal{A}, then X \neq \o
(ii) If X \in \mathcal{A} and Y \in \mathcal{A}, then X=Y or X \cap Y= \o
(iii)\bigcup_{X \in \mathal{A}}X=A
That's long winded! A "partition" of a set, A, is a collection of subsets of A such that every member of A is in one and only one of the subsets. Here, the members of A are 1, 2, 3, 4, 5, 6, 7. Is every one of those numbers in one of the given subsets? Is any number in more than one?

I found this to be a definition for an equivalence class:
In mathematics, given a set X and an equivalence relation ~ on X, the equivalence class of an element a in X is the subset of all elements in X which are equivalent to a:

\left[a\right]={x \in X|x \sim a}

Okay, and the relation x T y is defined by "x T y if and only if the largest integer less than or equal to x is the same as the largest integer less than or equal to y".

Now try some examples. What numbers are equivalent to 0? to 1/2? to 5/4? to \pi?
 


All the numbers in a subset are only in one subset once.

-What do you mean by what numbers are equivalent to 0, 1/2, pi, etc
 

Similar threads

Replies
6
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
13
Views
3K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
Replies
1
Views
2K
Replies
3
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K