Tic: Relations & Sets: A Subset Possibility?

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SUMMARY

A relation can indeed be a subset of another relation, as demonstrated in the discussion regarding the relations X: A <--> B, Y: B <--> C, and Z: A <--> C. The relational composition of X and Y can be a subset of Z if Z includes all pairs resulting from the composition of X and Y. The definition of a binary relation as a set of pairs (x,y) is crucial for understanding this concept. The discussion emphasizes the importance of recognizing the subset relationship in the context of relational algebra.

PREREQUISITES
  • Understanding of binary relations and their properties
  • Familiarity with relational algebra concepts
  • Knowledge of set theory, specifically ordered pairs and subsets
  • Basic grasp of relational composition
NEXT STEPS
  • Study the principles of relational algebra and its operations
  • Explore set theory, focusing on subsets and ordered pairs
  • Learn about relational composition and its implications in database theory
  • Investigate examples of relations in practical applications, such as SQL databases
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This discussion is beneficial for students of mathematics, computer science professionals, and anyone interested in the theoretical foundations of database relations and set theory.

StIgM@
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Hello guys,
I am new to this forum.

I have a question:
A relation can be subset of some other relation?

For example? I have the relations
X: A <---> B
Y: B <---> C
Z: A <---> C

X relational composition Y can be a subset of Z (if Z contains all the pairs of the composition)

Thanks in advance for your help

StIgM@
 
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A binary relation is a set R of pairs (x,y) such that (x,y) is in R if an only if x is related to y. If x and y are related we write xRy. In general, a n-ary relation in general is a set of n-tuples. A subset of a relation R is merely a subset of the set R.

In set theory we usually define a relation as an ordered triple (A,B,R), where R is a subset of A x B.
 
Ok, I get your meaning but you didn't give an answer to my example!

Do you know if this is correct?

For example? I have the relations
X: A <---> B
Y: B <---> C
Z: A <---> C

X relational composition Y can be a subset of Z (if Z contains all the pairs of the composition)
?
 
StIgM@ said:
Ok, I get your meaning but you didn't give an answer to my example!

Do you know if this is correct?

For example? I have the relations
X: A <---> B
Y: B <---> C
Z: A <---> C

X relational composition Y can be a subset of Z (if Z contains all the pairs of the composition)
?

This is not really the right place to post homework-style questions. Also Jarle's post contains the answer to your question in the clever wording of the definition. Good luck, welcome to the forum!
 

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