Prove the Theorem: Let A and B be regularly closed sets in a metric space X. If aAnBº + then Aºn B° + Ø.
Let (X, d) be a metric space, and let ACX be a subset (a) (3 pts) Let x E X. Write the definition of d(x, A) (b) (7 pts) Assume A is closed. Prove that d(x,A-0 if and only if x E A. Let (X, d) be a metric space, and let ACX be a subset (a) (3 pts) Let x E X. Write the definition of d(x, A) (b) (7 pts) Assume A is closed. Prove that d(x,A-0 if...
Problem 1. Let (X, d) be a metric space and t the metric topology on X. (a) Fix a E X. Prove that the map f :(X, T) + R defined by f(x) = d(a, x) is continuous. (b) If {x'n} and {yn} are Cauchy sequences, prove that {d(In, Yn)} is a Cauchy sequence in R.
A. Let (X, d) be a metric space so that for every E X and every r>0 the closed ball N,(z) = {ye X : d(y, z) < r} is com pact. Let be a homeomorphism. (1) Prove that f"-+m-fn。fm for all n, m E Z. (2) Let z E X and suppose that F, {fn (z) : n E 2) is a closed subset of X Prove that F is a discrete subset of X (A subset Y C...
In the following exercises, consider the metric space R with the discrete metric and the subset A [0, 1 C R. 15) True/False: A is closed. 16) True/False: A is open 17) True/False: Every point of A is a limit point of A. 18) Calculate the boundary of A. 19) True/False: For all Xo E X and all ε > 0, if B(x0, e) contains a point of A besides xo, then A C B(xo, e) In the following exercises,...
(TOPOLOGY) Prove the following using the defintion: Exercise 56. Let (M, d) be a metric space and let k be a positive real number. We have shown that the function dk defined by dx(x, y) = kd(x,y) is a metric on M. Let Me denote M with metric d and let M denote M with metric dk. 1. Let f: Md+Mk be defined by f(x) = r. Show that f is continuous. 2. Let g: Mx + Md be defined...
5. Let X be a metric space. (a) Let x E X be an isolated point. Prove that the only sequences in X that converge to a are the sequences that are eventually constant (b) Prove that the only convergent sequences in a discrete metric space (See Problem 8 on page 79 for the definitions of "isolated" and "discrete.") with tail a,z,x.... are the eventually constant sequences.
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,...
Jet f be continuons one to one m compact metric space X onto a metric space Y. Prove that f'Y ~ X is continuoms (Hint: use this let X and Y e metric space, and let f be function from X to Y which is one to one and onto then the following three statments are equivalent. frs open, f is closed, f is continuous.
1. Let (X, d) be a metric space, and U, V, W CX subsets of X. (a) (i) Define what it means for U to be open. (ii) Define what it means for V to be closed. (iii) Define what it means for W to be compact. (b) Prove that in a metric space a compact subset is closed.