Proving (A⊕B)∩A= A-B: A Simple Guide

  • MHB
  • Thread starter putiiik
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In summary, there are various ways to prove that (A⊕B)∩A= A-B and it depends on the course which method is used. The first method involves using the fundamental identities of set algebra and it is important to be familiar with them. The "direct sum" of sets, denoted by A⊕B, is defined as the symmetric difference of A and B. This may seem strange since the "+" symbol typically represents addition, but it is actually the union of both sets except for their intersection. This is why it is called the symmetric difference.
  • #1
putiiik
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Prove that (A⊕B)∩A= A-B! Thank you!
 
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  • #2
There are various ways of proving this: using the fundamental identities of set algebra, using Euler-Venn diagrams, by definition using mutual inclusion of the left- and right-hand sides, etc. Which one is used in your course? And if it is the first method, are you familiar with the fundamental identities?
 
  • #3
For arbitrary sets, union $A\cup B$, intersection $A\cap B$, and difference A\ B, are defined but how are you defining the "direct sum" $A\bigoplus B$ of sets?
 
  • #4
  • #5
It seems very strange to us a "+" symbol to mean a "difference".
 
  • #6
Country Boy said:
It seems very strange to us a "+" symbol to mean a "difference".
It's the union of both sets except for their intersection.
As such a "+" seems appropriate.
It's just that to define it, we typically take the union of the 2 mutual differences, which is apparently why it is called symmetric difference.
 

FAQ: Proving (A⊕B)∩A= A-B: A Simple Guide

What is the purpose of proving (A⊕B)∩A= A-B?

The purpose of proving (A⊕B)∩A= A-B is to establish the equality between two mathematical expressions. This allows for simplification and better understanding of the relationship between the sets A and B.

What is the definition of (A⊕B)∩A?

The expression (A⊕B)∩A represents the intersection of the symmetric difference of sets A and B with set A. In other words, it includes all elements that are in either A or B, but not both, and also in A.

How do you prove (A⊕B)∩A= A-B?

To prove (A⊕B)∩A= A-B, you can use the definition of symmetric difference and intersection, along with basic set operations such as union and complement. You can also use logical equivalences and properties of sets to show that both expressions are equivalent.

What are the steps involved in proving (A⊕B)∩A= A-B?

The steps involved in proving (A⊕B)∩A= A-B may vary, but generally they include: 1) rewriting the expressions using definitions and properties of sets, 2) showing that both expressions are equivalent through logical equivalences, 3) using set operations to simplify the expressions, and 4) providing a clear and concise explanation of the proof.

Why is proving (A⊕B)∩A= A-B important in mathematics?

Proving (A⊕B)∩A= A-B is important in mathematics because it allows for a better understanding of the relationship between sets and their operations. It also helps to simplify complex expressions and can be used as a tool to solve more advanced mathematical problems. Additionally, proving this equality can serve as a basis for more complex proofs and theorems.

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