### Metric Space Exercises

You may work alone or in a group of up to 3 people and turn in 1 per group.
Make copies of your work so that you are prepared to present any
of the exercises after you turn it in.
### Problem 1

Use the following from Sibley's Geometric Viewpoint
to help you, but write out a complete
proof that SAS does not hold in R^{2} with the taxicab metric.
### Problem 2

Mendelson p. 34 # 3
### Problem 3

Let (X,d) and (Y,p) be metric spaces. Assume that
f: X --> Y is an isometry, ie that f preserves distances. Prove that
f is continuous.
### Problem 4

Let (X,d) be a metric space, x in X and Epsilon > 0.
Prove that B_d (x, Epsilon) is an open set.
### Graduate Problem

Mendelson p. 35 #8

### Giving Proper References

Be sure to give proper reference where it is due. Even if you find ideas
or a proof elsewhere, all work needs to be written up in your own
(group's) words and explanations, although you should still reference
the original work or person.