M
k
⊆ M (k ∈ N), M
0
⊆ M
1
⊆
M
2
⊆ . . .
M
0
M
k
M
k+1
M
k
I(F ) (a
1
, a
2
, . . . , a
m
) F m
T a
1
, a
2
, . . . , a
m
M
k
M
k+1
I(c) c
T e(x, A, φ) A T
x φ : X → M
k
• ψ ∈ φ
x
val(I, ψ, A) = 1
e(x, A, φ) = ψ(x)
ψ(x)
A x val(I, ψ, A)
• val(I, ψ, A) = 0 ψ ∈ φ
x
e(x, A, φ) = a
0
a
0
M
0
M
k
N =
S
∞
k=0
M
k
M
k
N
F m T a
1
, a
2
, . . . , a
m
∈
N k a
1
, a
2
, . . . , a
m
∈ M
k
I(F )(a
1
, a
2
, . . . , a
m
) ∈
M
k+1
⊆ N val(I, φ, A) = val(I
N
, φ, A)
φ : X → N
A I
N
(P )
N I(P ) A = ¬B, A = B ⇒ C, A = B ∨C
A = B ∧ C
B C A = ∃xB
B x, y
1
, y
2
, . . . , y
m
k
φ(x) φ(y
i
) (i = 1, 2, . . . , m) M
k
val(I, φ, A) = 0 val(I, ψ, B) = 0 ψ ∈ φ
x
val(I
N
, ψ, B) = 0 ψ : T → N, ψ ∈ φ
x
val(I
N
, φ, A) = 0 val(I, φ, A) = 1 val(I, ψ, B) = 1
ψ ∈ φ
x
val(I, ψ, B) = 1 ψ ∈ φ
x
ψ(x) = e(x, B, φ) ∈ M
k+1
⊆ N val(I
N
, φ, A) = 1
A = ∀xB ∀xB ≡ ¬∃x¬B
M
0
M
M
0
N ⊆ M
0
M
0
R
0
R