Question

Show that the following collections τ of subsets of X form a topology in the given...

Show that the following collections τ of subsets of X form a topology in the given space.

a) Let X = R with τ consisting of all subsets B of R such that R\B contains finitely many elements or is all of R.

b) Let X = {a, b, c} and τ = {∅, {c}, {a, c}, {b, c}, {a, b, c}}.

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