Equivalence of d and p Metrics on X

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SUMMARY

The discussion centers on proving the equivalence of the metrics d and p on the space X, where p is defined as p(x,y) = d(x,y) / (1 + d(x,y)). It is established that if d is a metric, then p is also a metric. The participants explore the Lipschitz condition, specifically the existence of constants A and B such that Ap ≤ d ≤ Bp, to demonstrate this equivalence. The conversation emphasizes that two metrics are equivalent if they induce the same topology, particularly focusing on the behavior of metrics for nearby points.

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Homework Statement


Show that d and p are equivalent metrics on X where p=d(x,y)/(1+d(x,y))



Homework Equations


ive proved already that p is indeed a metric too (if d is a metric).


The Attempt at a Solution



I believe I am supposed to use the Lipschitz condition where there exits constants A and B st for all x,y,

Ap<=d<=Bp

but i think i can actually prove that one of these two constants cannot exist... and i using the wrong definitions? Thanks!
 
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Two metrics are equivalent if they induce the same topology. Isn't that the real definition? It is true that Ap<=d<=Bp shows that. But isn't it also true that for a metric topology what really determines the topology is the 'small' sets? If you can show there is a condition like that for say d<=1. That would also suffice, it doesn't have to hold for ALL x,y. Just for nearby ones.
 

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