ΓG
Th(G) = Th(Γ) G
Γ0Γ
X= (Γ,{Xv}v∈V(Γ),{Xe}e∈E(Γ))
Xe→XvXe→Xwe= (v, w)
X XvXe
Xe×[0,1]
X1, X2
ij:§1→XjX1X2
G= (Γ,{Gv}v∈V(Γ),{Ge}e∈E(Γ))
Xe→XvXe→Xwe= (v, w)
X= (Γ,{Xv}v∈V(Γ),{Xe}e∈E(Γ))Xv
π1(Xv) = GvXeπ1(Xe) = GeXe→Xv
Ge→Gv
π1(X)
ΓGe'Z
π1(G) = G1∗ZG2
G= (Γ,{Gv}v∈V(Γ),{Ge}e∈E(Γ))
v Gv
e7→ [iv(Ge)] []
v
G0G
(G, G0, r)r:G→G0
G= (Γ,{Gv}v∈V(Γ),{Ge}e∈E(Γ))
V(Γ) = Vs(Γ) tVr(Γ) v∈Vs(Γ)
−2
ΓVsVr
G0Gvv∈V(Γ)
v∈Vs(Γ) r(Gv)
H G H
H H ≤G0≤ · · · ≤ Gm
•G0=H∗S1∗. . . ∗Sq∗FkSj
F
•i ri:Gi→Gi−1(Gi, Gi−1, ri)