- is
countable if
either it is
finite or it can be made in one to one
correspondence with the set of
natural numbers. Equivalently, a set is
countable if...
- second-
countable space is said to
satisfy the
second axiom of
countability. Like
other countability axioms, the
property of
being second-
countable restricts...
- Fréchet–Urysohn space. First-
countability is
strictly weaker than second-
countability.
Every second-
countable space is first-
countable, but any
uncountable discrete...
- mathematics, an
axiom of
countability is a
property of
certain mathematical objects that ****erts the
existence of a
countable set with
certain properties...
-
generating set
Countably generated space, a
topological space in
which the
topology is
determined by its
countable subsets Countably generated module...
-
Countable Corporation (aka
Countable) is a Software-as-a-Service (SaaS)
company based in San Francisco. The
company was
founded in 2013 by its CEO Bart...
-
ordered set X is said to
satisfy the
countable chain condition, or to be ccc, if
every strong antichain in X is
countable.
There are
really two conditions:...
-
determined by its
values on the
countable dense subset.
Contrast separability with the
related notion of
second countability,
which is in
general stronger...
- The
cocountable topology or
countable complement topology on any set X
consists of the
empty set and all
cocountable subsets of X, that is all sets whose...
-
complement in X is a
countable set. In
other words, Y
contains all but
countably many
elements of X.
Since the
rational numbers are a
countable subset of the...
