Finding the Inverse Matrix for a Finite Set Relation R

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SUMMARY

The discussion focuses on finding the inverse matrix \( R^{-1} \) for a finite set relation \( R \) represented by a matrix. The example provided uses the set \( A = \{1, 2, 3\} \) with the relation \( R = \{(1, 1), (1, 3), (2, 3)\} \), resulting in the matrix \( \begin{pmatrix} 1 & 0 & 1 \\ 0 & 0 & 1 \\ 0 & 0 & 0 \end{pmatrix} \). To find the inverse relation \( R^{-1} \), the condition \( R \cdot R^{-1} = I \) (identity matrix) must be satisfied. The discussion emphasizes the relationship between the original and inverse matrices.

PREREQUISITES
  • Understanding of finite set relations
  • Knowledge of matrix representation of relations
  • Familiarity with matrix multiplication
  • Concept of identity matrices in linear algebra
NEXT STEPS
  • Study the properties of inverse matrices in linear algebra
  • Learn how to construct matrices from relations in discrete mathematics
  • Explore matrix multiplication techniques and their implications
  • Investigate the identity matrix and its role in matrix operations
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Students of discrete mathematics, mathematicians interested in linear algebra, and educators teaching matrix theory and relations.

brad sue
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Hi .
I have this question( discrete math) :
How can the matrix for R-1 , the inverse of the relation R, be found from the matrix representing R, when R is a relation a finite set A.

How can I do this problem?
 
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When in doubt, try a simple example. Suppose A= {1, 2, 3} and R is defined as {(1, 1), (1, 3), (2, 3)} (I just made that up pretty much at random. Remember that a "relation on A" is just a collection of pairs of members of A.) Now, the "matrix representing R" is the matrix having 1 in the "a row, b column" when (a,b) is in R, 0 otherwise. here, labeling the rows and columns 1, 2, 3 in that order, the matrix is
[tex]\left(\begin{array}{ccc}1 & 0 & 1\\0 & 0 &1 \\0 & 0 & 0\end{array}\right)[/tex].

What is the relation R-1? What matrix represents it? How are the two matrices related?
 
HallsofIvy said:
What is the relation R-1? What matrix represents it? How are the two matrices related?

I think, we need to find a matrix R-1 such that R*R-1=indentity matrix
 

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