axiom of countability
the property satisfied by a topological space in which the neighborhood system of each point has a base consisting of a countable number of neighborhoods (first axiom of countability) or the property satisfied by a topological space that has a base for its topology consisting of a countable number of subsets of the space (second axiom of countability).
9 Common Grammatical PitfallsRead more in this article about some frequently asked questions and fun facts related to our definitions.
When To Use “A,” “An,” And “The”Articles are words that make it clear whether a noun refers to something specific or something general. The English language has only three articles: a, an, and the. This stanza from Emily Dickinson’s poem “A Bird Came Down the Walk” demonstrates the use of all three: A Bird came down the Walk— He did not know I saw— He bit an Angleworm in halves And …
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019