Let (Q, d) be the metric space consisting of the set Q of rational numbers with...
Let (Q, d) be the metric space consisting of the set Q of rational numbers with the standard metric d(x, y) = |x-yl. Show that the Heine Borel theorem fails for (Q,d). In other words, show that (Q, d) has a subset SCQ that is closed and bounded, but not compact
1. Let (Q, d) be the metric space consisting of the set Q of rational numbers with the standard metric d(x, y) = (x – yl. Show that the Heine-Borel theorem fails for (Q, d). In other words, show that (Q, d) has a subset SCQ that is closed and bounded, but not compact (8 points).
1.5.7 Prove the following separately Theorem 1.5.10. Let (X,d) be a metric space. (a) IfY is a compact subset of X, and Z C Y, then Z is compact if and only if Z is closed (b) IfY. Y are a finite collection of compact subsets of X, then their union Y1 U...UYn is also compact. (c) Every finite subset of X (including the empty set) is compact.
Let (X, d) be an infinite discrete metric space. Prove that any infinite subset of X is closed and bounded but NOT compact
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.
Using only the definition of compact sets in a metric space, give examples of: (a) A nonempty bounded set in (R", dp), for n > 2 and 1 < pく00, which is not compact. (b) A bounded subset Y of R such that (Y, dy) contains nonempty closed and bounded subsets which are not compact (here dy is the metric inherited from the usual metric in R) Using only the definition of compact sets in a metric space, give examples...
Real Analysis II Please do it without using Heine-Borel's theorem and do it only if you're sure Problem: Let E be a closed bounded subset of En and r be any function mapping E to (0,∞). Then there exists finitely many points yi ∈ E, i = 1,...,N such that Here Br(yi)(yi) is the open ball (neighborhood) of radius r(yi) centered at yi. Also, following definitions & theorems should help that E CUBy Definition. A subset S of a topological...
Suppose we tried to apply our real analysis definitions/methods to the set of rational numbers Q. In other words, in the definitions, we only consider rational numbers. E.g., [0, 1] now means [0, 1] ∩ Q, etc. In this setting: (a) Find an open cover of [0, 1] that contains no finite subcover. Hint: Fix an irrational number α ∈ [0, 1] (as a subset of the reals now!) and for each (rational) q ∈ [0, 1] look for an...
It's given the following metric space [ir?,d) with the euclidean norm and the set M= {Ixoy)ER?: Osxs1, Osyste} show or disprove that a) M is a closed set b) M is a bounded set c) M is compact
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....