- #1
A.MHF
- 26
- 1
Homework Statement
So I was doing this problem in Munkres's Topology book:
Determine whether the statement is true or false, If a double implication fails, determine whether one or the other of the possible implications holds:
A ⊂ B or A ⊂ C ⇔ A ⊂ ( B ∪ C )
Homework Equations
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The Attempt at a Solution
I know that the ⇒ direction is true because (x∈A→x∈B or x∈A→x∈C)⇒(x∈A→(x∈B or x∈C))
For the other direction, I thought at first that it's true, but I checked some online answers and what I found is it's false. I thought it's true because what I had in mind is the word "or" stands for "either A is a subset of B, or A is a subset of C, or both". And if A is a subset of the union of B and C, then it's implied that A is a subset of at least one of them. What am I getting wrong?
This is the answer that I found online:
If the LHS statement is true then for each