A
string (or
1-brane) is a one-dimensional (
1d) curvilinear
path integral (integrand) with (at most) two (
2)
endpoints (in/
input and out/
output) called
nuts.
Strings may be
open🔓 or
closed🔒, but not both. (see also
brane,
SMALL brane,
loopstring,
string ludology,
thread,
walk)
