- #1
XodoX
- 203
- 0
I don't understand it.
A has n elements, and B has m elements. Give the exact maximum/minimum of
1) A [itex]\bigcup[/itex] B
2) A [itex]\bigcap[/itex] B
3) A X BI don't understand the solution to this..
1) If A and B are a disjunction ( A[itex]\bigcap[/itex] B = ∅), then the max of A [itex]\bigcup[/itex] B is:
A [itex]\bigcap[/itex] B = ∅ -> |A[itex]\bigcup[/itex]B| = m + nIf A is a subset of B (A[itex]\subseteq[/itex]B) or B a subset of A (B [itex]\subseteq[/itex] A),
then the min of A and B is:
A[itex]\subseteq[/itex]B -> |A[itex]\bigcup[/itex]B| = |B| = m
B[itex]\subseteq[/itex]A -> |A[itex]\bigcup[/itex]B| = |A| = nSo you're basically saying the min here is m and n. I understand that. I just don't get the explanation of it. I have to show why it's the min.
Therefore, the max of A [itex]\bigcup[/itex] B is:
max(n,m) [itex]\leq[/itex] |A[itex]\bigcup[/itex]B| [itex]\leq[/itex] n+m
Don't get this one. In words: The max is no greater than n+m. But it says it's less or equal to A and B. So you're already assuming A and B is the max?
2 and 3 have the same confusing explanations.
A has n elements, and B has m elements. Give the exact maximum/minimum of
1) A [itex]\bigcup[/itex] B
2) A [itex]\bigcap[/itex] B
3) A X BI don't understand the solution to this..
1) If A and B are a disjunction ( A[itex]\bigcap[/itex] B = ∅), then the max of A [itex]\bigcup[/itex] B is:
A [itex]\bigcap[/itex] B = ∅ -> |A[itex]\bigcup[/itex]B| = m + nIf A is a subset of B (A[itex]\subseteq[/itex]B) or B a subset of A (B [itex]\subseteq[/itex] A),
then the min of A and B is:
A[itex]\subseteq[/itex]B -> |A[itex]\bigcup[/itex]B| = |B| = m
B[itex]\subseteq[/itex]A -> |A[itex]\bigcup[/itex]B| = |A| = nSo you're basically saying the min here is m and n. I understand that. I just don't get the explanation of it. I have to show why it's the min.
Therefore, the max of A [itex]\bigcup[/itex] B is:
max(n,m) [itex]\leq[/itex] |A[itex]\bigcup[/itex]B| [itex]\leq[/itex] n+m
Don't get this one. In words: The max is no greater than n+m. But it says it's less or equal to A and B. So you're already assuming A and B is the max?
2 and 3 have the same confusing explanations.