Prove or provide a counterexample
If f is T_C−T_U continuous, then f is T_U−T_C continuous.
Where T_C is the open half-line topology and T_U is the usual
topology.
Let X be a compact space and let Y be a Hausdorff space. Let f ∶
X → Y be continuous. Show that the image of any closed set in X
under f must also be closed in Y .
State a complete proof or disprove with an explicit
counterexample:
a) Every stable matching is also Pareto optimal.
b) Every Pareto optimal matching is also stable.
Topology
(a) Prove that the interval [0,1] with the subspace topology is
connected from basic principles.
(b) Prove that the interval [0,1] with the subspace topology is
compact from basic principles.
a) Prove that if X is Hausdorff, then X is T1
b) Give an example of a space that is T1 , but not
Hausdorff. Prove that the space you give is T1 and prove
it is not Hausdorff.
Calculate the relative (sub-space) topology with respect to the
usual (metric) topology in R (the set of real numbers), for the
following sub-sets of R:
X = Z, where Z represents the set of integers
Y = {0} U {1 / n | n is an integer such that n> 0}
Calculate (establish who are) the closed (relative) sets for the
X and Y sub-spaces defined above.
Is {0} open relative to X?
Is {0} open relative to Y?