sp1 . sp2 . sp3 ... . spn
a sequence is a time ordered list of one or more superpositions
notationally we separate the superpositions using the infix dot symbol
a sequence simply represents the change of a system with respect to time
they are the most general object type in the SDB
and all operators in the language map sequences to sequences
because all operators map sequences to sequences we can arbitrarily chain operators into so called operator sequences