x1 is a rule prescribing/mandating/requiring x2 (event/state) within system/community x3.
Regulation, prescription (also x2), principle, requirement (also x2), prescribe, require (conditions are usually contained within x2); x1 is regulatory; x2, x3 are regulated. See also flalu, ritli, cmavo list ja'i, marde, tcaci, tinbe, zekri.