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domains

In mathematics, a domain of a function or relation is the set of input values for which the function is defined. If a function f maps from a domain A to a codomain B, A is called the domain. The codomain is B. The domain determines where the formula can be evaluated without undefined operations. The domain may be distinct from the range of outputs the function actually produces.

Common examples include the domain of sqrt(x) being x ≥ 0; the domain of 1/x being x ≠

In computing, a domain also refers to a domain name in the Domain Name System. A domain

Beyond mathematics and networking, domain can denote an area or context of activity, knowledge, or influence.

0;
and
the
domain
of
log(x)
being
x
>
0.
For
functions
of
several
variables
the
domain
is
a
subset
of
R^n
defined
by
constraints
such
as
x
>
0
and
y
≥
2.
The
domain
may
be
restricted
to
ensure
properties
such
as
continuity
or
differentiability.
is
a
hierarchical
naming
space
used
to
identify
resources
on
the
Internet.
Domain
names
are
read
from
right
to
left
and
commonly
end
with
a
top-level
domain
such
as
.com
or
.org,
or
a
country
code.
DNS
translates
names
to
IP
addresses
and
supports
a
range
of
records
(A,
CNAME,
MX,
TXT)
used
to
route
traffic
and
verify
identity.
In
logic,
the
domain
of
discourse
is
the
set
of
objects
under
consideration.
In
problem
solving,
the
domain
defines
where
rules
apply
and
which
values
are
admissible.