x1, . . . , xnt
IσI
τ={x1/t1, . . . , xn/tn}d1. . . dn[ti]I,σ =di
[t]I,σ[x1:=d1]...[xn:=dn]= [τ(t)]I,σ
x1, . . . , xnG
IσI
τ={x1/t1, . . . , xn/tn}d1. . . dn
[ti]I,σ =di[G]I,σ[x1:=d1]...[xn:=dn]= [τ(G)]I,σ
G=r(x1, x2)τ={x1/a, x2/s(a)}
I(r)(n, m) = Vn < m I(a) = 0 I(s)(n) = n+ 1
B0, B1, B2, . . .
Σ
B0
BiV F
BiBi+1
A1
q(a), q(b), r(a), r(b)
A2
q(a), q(b), q(s(a)), q(s(b)), q(s(s(a))), q(s(s(b))), . . .