
doi: 10.1007/bf01054225
A subspace X of a topological space Y is said to be bounded in Y if every continuous, real-valued function on Y is bounded on X. Using the elegant observation that a necessary and sufficient condition for boundedness of X in Y is that only finitely many elements of any locally finite family of sets open in Y can intersect X, it is shown that the cartesian product of an arbitrary family of bounded subsets of topological groups is bounded in the product of the groups. [This, of course, generalizes the well-known theorem of Comfort and Ross.] It is also shown that a continuous pseudometric on a topological group is uniformly continuous on any bounded subspace, as is any real-valued continuous function defined on G. Furthermore, the universal, two-sided, left and right uniformities from the group are equal on X. If G is algebraically generated by X and X is bounded, then any real-valued function on X can be factored through a continuous homomorphism onto a group of countable weight. A union of countably many bounded subspaces is said to be sigma-bounded. A (Tychonoff) space X is then sigma-bounded iff all of the following are also sigma-bounded: the free topological group on X, the free topological Abelian group on X, and the free linear locally convex space on X.
bounded subsets of topological groups, free topological group, Compactness, zero-dimensional group, h-embedded, continuous pseudometric, uniformly continuous, inverse limit, open homomorphisms, free linear locally convex space, products of pseudocompact topological groups, theorem of Comfort and Ross, closed subgroups, sigma- bounded, Structure of general topological groups, uniformities
bounded subsets of topological groups, free topological group, Compactness, zero-dimensional group, h-embedded, continuous pseudometric, uniformly continuous, inverse limit, open homomorphisms, free linear locally convex space, products of pseudocompact topological groups, theorem of Comfort and Ross, closed subgroups, sigma- bounded, Structure of general topological groups, uniformities
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