Definition·D079
Singleton sequence
The length-one finite sequence containing just one element.
For a set
and
:
In words
The singleton sequence of an element is the length-one sequence whose only entry, at position 0, is that element.
Rests onno axioms yet
Never needed: F02 · F03 · F04 · F05 · F06 · F08 · F09 · F10 · F11 · F12 · F13 · F14 · A01 · A02 · A03 · A04 · A05 · A06 · A07 · A08 (computed from the citation graph, not asserted).
Remarks
: it is a function with domain
(D074), since
is its only pair. The basic building block for growing longer sequences via concatenation one symbol at a time; used to seed term and formula formation over a language's alphabet.