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5. Let A and B be compact subsets of R. (a) Prove that AnB is compact...
5- Recall that a set KCR is said to be compact if every open cover for K has a finite subcover 5-1) Use the above definition to prove that if A and B are two compact subsets of R then AUB is compact induction to show that a finite union of compact subsets of R is compact. 5-2) Now use 5-3) Let A be a nonempty finite subset of R. Prove that A is compact 5-4) Give an example of...
A,C,G please 1. Let A, B, and C be subsets of some universal set u. Prove the following statements from Theorem 4.2.6 (a) AUA=/1 and AnA=A. (b) AUO- A and An. (c) AnB C A and ACAUB (d) AU(BUC)= (A U B) U C and An(B n C)-(A n B) n C. (e) AUB=BUA and A n B = B n A. (f) AU(BnC) (AU B) n(AUC) (g) (A U B) = A n B (h) AUA=1( and An-=0. hore...
6. Let A, B, and C be subsets of some universal set U. Prove or disprove each of the following: * (a) (A n B)-C = (A-C) n (B-C) (b) (AUB)-(A nB)=(A-B) U (B-A) 6. Let A, B, and C be subsets of some universal set U. Prove or disprove each of the following: * (a) (A n B)-C = (A-C) n (B-C) (b) (AUB)-(A nB)=(A-B) U (B-A)
1. (a) Prove that a closed subset of a compact set is compact. (b) Let a, b € R and f: R → R, x H ax + b. Prove that f is continuous. Is f uniformly continuous?
Let A, B be non-empty, bounded subsets of R. a) If the statement is true, prove it. If the statement is false, give a counterexample: sup(AUB) = max(sup(A), sup(B)}. b) If the statement is true, prove it. If the statement is false, give a counterexample: If An B + Ø, then sup(A n B) = min{sup(A), sup(B)}. E 选择文件
. Let C be a collection of open subsets of R. Thus, C is a set whose elements are open subsets of R. Note that C need not be finite, or even countable. (a) Prove that the union U S is also an open subset of R. SEC (b) Assuming C is finite, prove that the intersection n S is an open subset of R. SEC (c) Give an example where C is infinite and n S is not open....
7. Suppose that A, B and C are subsets of a set X. Use examples to investigate the following sets. In each case, make a hypothesis. (b) (AUB) versus AnB (e) (An B)e versus Aen Be.
Please help me prove 2,4, and 5. Thank you Theorem 17. Let A, B and C be sets. Then the following statements are true: (1) AB CA; (2) B CAUB; (3) A CAUB; (4) AB=BA; (5) AU (AUC) = (AUB) UC; (6) An(BNC) = (ANB) nC; (7) An (BUC) = (ANB) U (ANC); (8) AU (BAC) = (AUB) n(AUC).
Question 6. a) Let A, B and C be open subsets of R. Prove that AnBn C is open. b) Give an example to show that the intersection of infinitely many open sets may not be open.
5. Let X be a topological space and let A and B be connected subsets of X. Prove that if AndB+, then AUB is connected.