Is \bigcap(F \cup G) equal to (\cap F)\bigcap(\cap G)?

  • Thread starter Klungo
  • Start date
In summary, the conversation discusses how to prove the set equality \bigcap(F \cup G)=(\cap F)\bigcap(\cap G). The attempt at a solution involves considering two cases: if S \in F or if S \in F and S \in G. However, the conversation ends with the suggestion to restart the proof and continue from the definition of the operation \bigcap.
  • #1
Klungo
136
1

Homework Statement


(Title is wrong)

I was able to prove the similar [itex] \bigcup(F \cup G)=(\cup F)\bigcup(\cup G) [/itex] but I'm not to sure how to go about this one.

Let F and G be nonempty families of sets. Prove
[itex] \bigcap(F \cup G)=(\cap F)\bigcap(\cap G) [/itex]

2. The attempt at a solution
To prove [itex]\bigcap(F \cup G) \subset (\cap F)\bigcap(\cap G)[/itex],
let [itex] x \subset \bigcap(F \cup G) [/itex] be arbitrary. Clearly, [itex] x \in S[/itex] for some set [itex] S \subset \bigcap F \cup G [/itex] containing all common elements in [itex] F \cup G [/itex]. We have [itex] S \in F \cup G.[/itex]

Do I go by..

We have two cases: (only one needs to be proven really.)
Case 1: [itex] If S \in F [/itex], clearly [itex] S \subset \cup F [/itex]...
(I'm stuck here)

or Do I go by...

Suppose [itex] S \in F [/itex] and [itex] S \in G [/itex]. Clearly [itex] S \subset \cup F [/itex] and [itex] S \subset \cup G [/itex]. (I'm stuck here)

I'll try proving the converse and restart the proof since I misread the problem.
 
Last edited:
Physics news on Phys.org
  • #2
By definition of the operation [itex]\bigcap[/itex], any x in [itex]\bigcap(F\cup G)[/itex] must be contained in EVERY SET of [itex]F\cup G[/itex]. Continue from here.
 

1. What is the meaning of "Prove: n(FuG) = (uF)n(uG)?"

The notation n(A) represents the number of elements in a set A. The statement "n(FuG) = (uF)n(uG)" is a mathematical expression that relates to the intersection of two sets, F and G, with the union of two sets, F and G. This expression is known as the distributive property of sets.

2. How is the distributive property of sets used to prove n(FuG) = (uF)n(uG)?

The distributive property of sets states that the intersection of two sets, A and B, with the union of two sets, C and D, is equal to the intersection of A with C and the intersection of A with D. This property can be applied to prove the equation n(FuG) = (uF)n(uG) by showing that the elements in both sets are the same.

3. Can you provide an example to illustrate the equation n(FuG) = (uF)n(uG)?

Let's say we have two sets, F = {1, 2, 3} and G = {2, 3, 4}. The intersection of these sets (FuG) is {2, 3}. The union of these sets is {1, 2, 3, 4}. By using the distributive property, we can see that the intersection of (uF) with (uG) is also {2, 3}. Therefore, n(FuG) = (uF)n(uG) since both sets contain the same elements.

4. Is the distributive property of sets always true?

Yes, the distributive property of sets is a fundamental property in set theory and is always true. It is a basic rule that governs the relationships between different sets and their elements.

5. How does the statement n(FuG) = (uF)n(uG) relate to other mathematical concepts?

The distributive property of sets is a specific case of the distributive property in algebra, where the intersection and union of sets are replaced by multiplication and addition, respectively. This statement also relates to other concepts in set theory, such as the commutative and associative properties, which govern the order and grouping of elements in sets.

Similar threads

  • Calculus and Beyond Homework Help
Replies
4
Views
824
  • Calculus and Beyond Homework Help
Replies
1
Views
516
  • Calculus and Beyond Homework Help
Replies
3
Views
972
  • Calculus and Beyond Homework Help
Replies
4
Views
935
  • Calculus and Beyond Homework Help
Replies
3
Views
756
  • Calculus and Beyond Homework Help
Replies
20
Views
2K
  • Calculus and Beyond Homework Help
Replies
3
Views
999
  • Calculus and Beyond Homework Help
Replies
12
Views
2K
  • Calculus and Beyond Homework Help
Replies
1
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
1K
Back
Top