TITLE: Notation for a subsequence of a sequence
QUESTION [11 upvotes]: If we have a sequence (an ordered list)
$$
S=(s_0,s_1,...,s_n).
$$
What is the notation for expressing that $S'$ is a (ordered) subsequence of $S$?

REPLY [3 votes]: I appreciate all the effort and attention put into this question in the last week. Unfortunately, the answer seems to be "there is no such standard notation". Some interesting ideas were generated nonetheless!