MHB Convergence in topological space

Julio1
Messages
66
Reaction score
0
Let $(X,\tau)$ an topological space. Show that $x_n\to_{n\to \infty} x$ if and only if $d(x_n,x)\to_{n\to \infty} 0.$

Hello, any idea for begin? Thanks.
 
Physics news on Phys.org
Hi Julio,

Is $d$ supposed to be a metric? If so, the problem statement makes little sense, since there non-metrizable topological spaces.
 
What definition of "limit" are you using? If, as your use of "d" implies, this is a metric space, that looks pretty much like the standard definition of "limit" in a metric space.
 
A sphere as topological manifold can be defined by gluing together the boundary of two disk. Basically one starts assigning each disk the subspace topology from ##\mathbb R^2## and then taking the quotient topology obtained by gluing their boundaries. Starting from the above definition of 2-sphere as topological manifold, shows that it is homeomorphic to the "embedded" sphere understood as subset of ##\mathbb R^3## in the subspace topology.
Back
Top