In mathematics, a sequence is an ordered collection of objects in which repetitions are allowed. Like a set, it contains members (also called elements, or terms). The number of elements (possibly infinite) is called the length of the sequence. Unlike a set, order matters, and exactly the same elements can appear multiple times at different positions in the sequence. Formally, a sequence can be defined as a function whose domain is a convex subset of the set of integers, such as ,
,
, or
.
For example, (M, A, R, Y) is a sequence of letters with the letter 'M' first and 'Y' last. This sequence differs from (A, R, M, Y). Also, the sequence (1, 1, 2, 3, 5, 8), which contains the number 1 at two different positions, is a valid sequence. Sequences can be finite, as in these examples, or infinite, such as the sequence of all even positive integers (2, 4, 6, ...). In computing and computer science, finite sequences are sometimes called strings, words or lists, the different names commonly corresponding to different ways to represent them in computer memory; infinite sequences are also called streams. The empty sequence ( ) is included in most notions of sequence, but may be excluded depending on the context.
In medicine, a sequence is a series of ordered consequences due to a single cause.
It differs from a syndrome in that seriality is more predictable: if A causes B, and B causes C, and C causes D, then D would not be seen if C is not seen. However, in less formal contexts, the term "syndrome" is sometimes used instead of sequence.
Examples include:
A sequence (Latin: sequentia) is a chant or hymn sung or recited during the liturgical celebration of the Eucharist for many Christian denominations, before the proclamation of the Gospel. By the time of the Council of Trent (1543–1563) there were sequences for many feasts in the Church's year.
The sequence has always been sung before the Gospel. The 2002 edition of the General Instruction of the Roman Missal, however, reversed the order and places the sequence before the Alleluia.
The form of this chant inspired a genre of Latin poetry written in a non-classical metre, often on a sacred Christian subject, which is also called a sequence.
The Latin sequence has its beginnings, as an artistic form, in early Christian hymns such as the Vexilla Regis of Venantius Fortunatus. Venantius modified the classical metres based on syllable quantity to an accentual metre more easily suitable to be chanted to music in Christian worship. In the ninth century, Hrabanus Maurus also moved away from classical metres to produce Christian hymns such as Veni Creator Spiritus.
i've been waiting all night
watching as this moonlight shines through your hair
and tell me this will never last
just tell me this is in the past
cause i'm all yours my dear
and you say, say that you were ready
but we know, you were never ready for whats to come
and watching from your window
thats all i can do
till hes done
till hes done with you
and i'm so impressed
by the way that she moves her hands down my chest
is this love again?
so go on
describing how i make you feel
cause its all i wanna hear
well maybe you're right
maybe now is not the time
for just a whisper of the things
that we hold dear
and maybe stars will grace your sky
like open arms and wonder why
she cries inside
bring these walls down again
cause i don't know where she goes