Définitions
1.NounA range; a continuous, infinite, one-dimensional set, possibly bounded by extremes.
2.NounSpecifically, a range of colours representing light (electromagnetic radiation) of contiguous frequencies; hence electromagnetic spectrum, visible spectrum, ultraviolet spectrum, etc. .mw-parser-output .defdate{font-size:smaller}
3.NounThe autism spectrum.
4.Noun(chemistry) The pattern of absorption or emission of radiation produced by a substance when subjected to energy (radiation, heat, electricity, etc.).
5.NounThe set of eigenvalues of a matrix.
6.NounOf a bounded linear operator A, the set of scalar values λ such that the operator A—λI, where I denotes the identity operator, does not have a bounded inverse; intended as a generalisation of the linear algebra sense.
7.NounAn abstract object in mathematics created from a commutative ring
R
{\displaystyle R}
and denoted
Spec
(
R
)
{\displaystyle \operatorname {Spec} (R)}
or
Spec
R
{\displaystyle \operatorname {Spec} R}
and said to be the spectrum of
R
{\displaystyle R}
; useful in the study of such rings for providing a geometric object which encodes many of the properties
R
{\displaystyle R}
, and in modern geometry for generalizing the notion of an algebraic variety to that of an affine scheme. Formally, the set of all prime ideals
R
{\displaystyle R}
equipped with the Zariski topology and augmented with a sheaf of rings called the structure sheaf, generated by the B-sheaf on the distinguished open sets
D
f
{\displaystyle D_{f}}
which assigns the localization of
R
{\displaystyle R}
at
f
{\displaystyle f}
to each set
D
f
{\displaystyle D_{f}}
, regarded as a ring of functions on
D
f
{\displaystyle D_{f}}
. See Spectrum of a ring on Wikipedia.Wikipedia
8.NounSpecter, apparition.
9.NounThe image of something seen that persists after the eyes are closed.