Proving (A-B) U C ≤ (A U B U C) - (A n B)

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In summary, the conversation is about a problem that involves proving a statement about sets, specifically (A - B) U C ≤ (A U B U C) - (A n B). The attempt at a solution involves using the subset relationship, but there is uncertainty about whether the solution is correct. The professor also mentions the possibility of finding a counterexample.
  • #1
taylor81792
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Homework Statement


The problem I have been given is to prove (A - B) U C is than less or equal to (A U B U C) - (A n B)

The Attempt at a Solution


I've tried starting off with just (A-B) U C. Then I would say how x ε c or x ε (A - B). Also if x ε a, then x ε c and x is not in b. If x ε c, since c is a subset of (A U B U C) , x ε (A U B U C). I don't know if this is right or where to go from here.
 
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  • #2
taylor81792 said:

Homework Statement


The problem I have been given is to prove (A - B) U C is than less or equal to (A U B U C) - (A n B)
This is a statement about sets, so the relationship is [itex]\subseteq[/itex], not ≤.
taylor81792 said:

The Attempt at a Solution


I've tried starting off with just (A-B) U C. Then I would say how x ε c or x ε (A - B). Also if x ε a, then x ε c and x is not in b.
Try to be more careful with the names of the sets, which are A, B, and C, not a, b, and c.
taylor81792 said:
If x ε c, since c is a subset of (A U B U C) , x ε (A U B U C). I don't know if this is right or where to go from here.
 
  • #3
i'd say that u can use:

AUBUC= lAl + lBl + lCl - lBnCl - lAnBl - lAnCl+lAnBnCl

but I'm not 100% positive just trying to give some help :)
 
  • #4
My professor said we can also try to prove or find a counterexample to this statement. Let A, B and C be sets. Then (A-B) U C = (A U B U C) - (A n B). I'm not really sure what she means by counterexample.
 
  • #5
mtayab1994 said:
i'd say that u can use:

AUBUC= lAl + lBl + lCl - lBnCl - lAnBl - lAnCl+lAnBnCl

but I'm not 100% positive just trying to give some help :)
Not only does that not help, it makes no sense. The left side is a set, the right side is a number.

Even if you meant |AUBUC| that is irrelevant to the problem. Showing that two sets have the same size does not prove they are the same set.
 

What is the meaning of the inequality (A-B) U C ≤ (A U B U C) - (A n B)?

The inequality (A-B) U C ≤ (A U B U C) - (A n B) states that the set of elements that are either in A or C, but not in B, is less than or equal to the set of elements that are in either A, B, or C, but not in both A and B.

What does it mean to "prove" this inequality?

To "prove" this inequality means to show that the statement is logically true and can be applied to all possible sets A, B, and C. This involves using mathematical reasoning, such as set operations and properties, to demonstrate that the left side of the inequality is always less than or equal to the right side.

Why is this inequality important in mathematics?

This inequality is important in mathematics because it helps to establish relationships between sets and their elements. It also plays a crucial role in understanding and solving more complex mathematical problems and proofs.

What is the process for proving this inequality?

The process for proving this inequality involves breaking down the expressions on both sides and using set operations and properties to manipulate them until they are equivalent. This is typically done through a series of logical steps and equations, and may involve using previously established theorems or definitions.

What are some real-world applications of this inequality?

This inequality has many real-world applications, such as in computer science, where it can be used to optimize algorithms and data structures. It is also used in statistics and probability to determine the likelihood of events occurring. Additionally, it has applications in various fields of science, such as genetics and ecology, to analyze and compare different sets of data.

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