Sime~Gen pair in which the Gen's basal selyn production rate matches the sime's basal selyn production rate. Matchmates may or may not be of opposite sexes. One of the classic locked-transfer dependancies (Lortuen - Orhuen - Torluen) can occur only if the pair has engaged in some selyn flow contact. Locked dependencies which cannot be broken short of death are mere romantic legend until the advent of the higher order channels who can have both their selyn systems matched and mated.
(Source: Index card file. Sime Surgeon --- http://www.simegen.com/sgfandom/rimonslibrary/surgeon/SURGEON1.html) Gen's selyn production rate is exact match of sime's selyn consumption rate. Lortuen possible only between matchmates.