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constructsuch

Constructsuch is a term used in mathematics and computer science to denote the act of explicitly constructing an object that satisfies a given property, typically to prove the existence of such an object. The word is formed from the verb construct and the phrase such that, and it is sometimes employed as a concise shorthand in proofs and formalizations.

Etymology and status: The expression does not constitute a formal, universally standardized technical term in all

Role in constructive mathematics and formal systems: In constructive mathematics, proving that there exists an x

Examples and implications: A typical constructsuch step might involve producing a specific natural number n that

See also: constructive mathematics, proof assistant, witness, constructive proof.

disciplines.
It
appears
mainly
as
an
informal
label
in
discussions
about
proof
strategies,
constructive
methods,
or
proof
assistants,
where
the
emphasis
is
on
providing
an
explicit
witness
rather
than
an
abstract
existence
claim.
with
a
property
P(x)
requires
producing
a
concrete
x
and
a
verification
that
P(x)
holds.
In
this
context,
to
"constructsuch"
an
x
is
the
central
goal
of
the
proof.
In
systemically
formal
settings
such
as
type
theory
and
proof
assistants
(for
example
Coq
or
Lean),
constructing
such
a
witness
is
encoded
as
a
function
or
term
that
yields
the
object
together
with
a
proof
that
it
satisfies
the
desired
property.
This
makes
existence
proofs
inherently
algorithmic
and,
in
principle,
executable.
satisfies
a
predicate
P(n)
and
a
proof
that
P(n)
holds.
By
contrast,
non-constructive
proofs
establish
existence
without
providing
a
concrete
witness,
which
is
not
acceptable
in
constructive
frameworks.
The
constructsuch
approach
has
implications
for
computability
and
program
extraction
from
proofs.