(5) Assume the canonical metric (the absolute difference between two real numbers) in R. Prove that...
Exercise 5 (based on Tao). Let (X,d) be an arbitrary metric space. Prove the following statements (1) If a sequence is convergent in X, all its subsequences are converging to the same limit as the original sequence. (2) If a subsequence of a Cauchy sequence is convergent, then the whole sequence is convergent to the same limit as the subsequence. (3) Suppose that (X,d) is complete and Y S X is closed in (X,d). Then the space (Y,dlyxy) is complete....
B2. (a) Let I denote the interval 0,1 and let C denote the space of continuous functions I-R. Define dsup(f,g)-sup |f(t)-g(t) and di(f.g)f (t)- g(t)ldt (f,g E C) tEI (i) Prove that dsup is a metric on C (ii) Prove that di is a metric on C. (You may use any standard properties of continuous functions and integrals, provided you make your reasoning clear.) 6 i) Let 1 denote the constant function on I with value 1. Give an explicit...
1. Let Xn ER be a sequence of real numbers. (a) Prove that if Xn is an increasing sequence bounded above, that is, if for all n, xn < Xn+1 and there exists M E R such that for all n E N, Xn < M, then limny Xn = sup{Xnin EN}. (b) Prove that if Xn is a decreasing sequence bounded below, that is, if for all n, Xn+1 < xn and there exists M ER such that for...
9. Suppose {X,.) are iid, EIX1く00, EX| = 0 and suppose that {cal is a bounded sequence of real numbers. Prove ή 2.cjX, → 0 a.s (If necessary, examine the proof of the SLLN.)
9. Suppose {X,.) are iid, EIX1く00, EX| = 0 and suppose that {cal is a bounded sequence of real numbers. Prove ή 2.cjX, → 0 a.s (If necessary, examine the proof of the SLLN.)
Prove that the real numbers have the least upper bound property, i.e. any bounded above subset S ⊆ R has a supremum if and only if the real numbers have the greatest lower bound property, i.e. any bounded below subset T ⊆ R has an infimum.
2. Let A be a nonempty set of real numbers bounded above. Define Prove that -A is bounded below, and that inf(-A) = -sup(A). -A={-a: aEA . (5 marks) (You may use results proved in class.) A = 0 , A is bounded above.
Example: Let {xn} be a sequence of real numbers. Show that Proposition 0.1 1. If r is bounded above, x = lim sup (r) if and only if For all 0 there is an NEN, such that x <x+e whenevern > N, and b. For all >0 and all M, there is n > M with x - e< In a.
Example: Let {xn} be a sequence of real numbers. Show that Proposition 0.1 1. If r is bounded above,...
(c) (5 marks) Give an example of i. a sequence of real numbers that is strictly increasing and converges to zero; ii. a sequence of real numbers that is not monotonic and converges to 2 iii. a sequence of real numbers that is bounded and divergent. (d) (5 marks) Calculate the first four terms in the Laurent series representation of e*.
Use the completeness axiom to show that every non empty subset of R (real numbers) that is bounded below has an infimum in R
REAL ANALYSIS Question 1 (1.1) Let A be a subset of R which is bounded above. Show that Sup A E A. (1.2) Let S be a subset of a metric space X. Prove that a subset T of S is closed in S if and only if T = SA K for some K which is closed in K. (1.3) Let A and B be two subsets of a metric space X. Recall that A°, the interior of A,...