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Adams-Franzosa 5.25) Let (X, dx) be a metric space. Assume pE X and AcX (a) Find an example showi...
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...
Let X be a metric space and let E C X. The boundary aE of E is defined by E EnE (a) Prove that DE = E\ E°. Here Eo is the set of all interior points of E; E° is called the interior of E (b) Prove that E is open if and only if EnaE Ø. (c) Prove that E is closed if and only if aE C E (d) For X R find Q (e) For X...
(1) Let (X,d) be a metric space and A, B CX be closed. Prove that A\B and B\A are separated
(1) Let (X,d) be a metric space and A, B CX be closed. Prove that A\B and B\A are separated
Let (X, d) be an infinite discrete metric space. Prove that any infinite subset of X is closed and bounded but NOT compact
Let (X, d) be a discrete space and let (Y, d′) be any metric space. Prove that any function f : (X, d) → (Y, d′) is continuous. (Namely, any function from a discrete space to any metric space is continuous.)
8) Prove that C([O, 1]) is a metric space with the metric .1 d(f, g) = / If(x)-g(x)| dx. 9) Let (X, di) and (Y, d2) be metric spaces. a) Prove that X × Y is a metric space with the metric b) Prove that X x Y is a metric space with the metric
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.
For each of the following metric spaces (X, d) and subsets A S X decide whether A is open, closed, neither or both. You do not need to justify your answers. (a) X-Z, d is the discrete metric. ACX is any subset (b) X = R2, d = d2 is the Euclidean metric. A = {(x, yje R2 : x-y) (c) X = R2, d = d2 is the Euclidean metric. A (0, 1) × {0).
(a) Let (X, d) be a metric space. Prove that the complement of any finite set F C X is open. Note: The empty set is open. (b) Let X be a set containing infinitely many elements, and let d be a metric on X. Prove that X contains an open set U such that U and its complement UC = X\U are both infinite.
3. (a) Prove the following: Cantor's Intersection Theorem: Let (X, d) be a complete metric space and {Anymore a nested sequence of non-empty closed sets whose diameters D(An) have limit 0. Then An has exactly one member. csc'anno proach onsdelered. c) Show that, in part (a), n A, may be empty if the requirement that the diameters