i, x:Id, a, b, c:Knd, T:Type.
@i: only members of [a; b; c] affect x :T Dsys
& (D:Dsys.
& (@i: only members of [a; b; c] affect x :TD & (D & ( realizes es.
& ( vartype(i;x) T & ( & e@i.
& ( & ((x after e) = (x when e) T kind(e) = a Knd kind(e) = b Knd kind(e) = c Knd)
& ( & & (kind(e) = a & ( & & (kind(e) = b Knd
& ( & & (kind(e) = c Knd
& ( & & ( (x after e) = (x when e) T))