countable

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Related to countably: Countably additive, Countably compact

countable

[′kau̇nt·ə·bəl]
(mathematics)
Either finite or denumerable. Also known as enumerable.

countable

(mathematics)
A term describing a set which is isomorphic to a subet of the natural numbers. A countable set has "countably many" elements. If the isomorphism is stated explicitly then the set is called "a counted set" or "an enumeration".

Examples of countable sets are any finite set, the natural numbers, integers, and rational numbers. The real numbers and complex numbers are not
References in periodicals archive ?
A subset of X is I-sequentially compact if and only if it is sequentially countably compact in the ordinary sense.
Even if this restriction were waived, the number of statements will still be no more than countably finite.
Now we make the additional assumption that X is also countably paracompact.
ii) strongly countably compact if every countable cover of X by preopen sets has a finite subcover and countably S-closed [resp:countably P-closed] if every countable cover of X by regular closed [resp: preclosed] sets has a finite subcover.
It is clear, that only for countably many g we have L([psi] [intersection]g) [not equal to] [empty set].
In this paper we prove that the eigenvalues of the underlying rational eigenproblem can be characterized as minmax values of a Rayleigh functional, from which we immediately obtain the existence of countably many real and positive eigenvalues.
To do so, we will need to work in the more general setting, Q[[A]], of rational species, that is, of countably summable linear combinations of molecular species with rational coefficients (v).
ii) Countably [nu]-compact space if every countable [nu]-open cover of it has a finite sub cover.
Example 5 Consider the Hopf algebra QSym of quasisymmetric functions in countably many variables, and the Hopf subalgebra Sym of symmetric functions.
Siwiec, Sequence-covering and countably bi-quotient mappings, General Topology Appl.
Second, we propose to derive identities between partitions by looking at suitable ideals in a polynomial ring in countably many variables endowed with a natural grading.
When P is countably infinite it is possible for the generating functions we have considered to be irrational.