Es sei
C
=
V
(
F
)
{\displaystyle {}C=V(F)}
F
=
α
X
2
+
β
X
Y
+
γ
Y
2
+
δ
X
+
ϵ
Y
+
η
{\displaystyle {}F=\alpha X^{2}+\beta XY+\gamma Y^{2}+\delta X+\epsilon Y+\eta \,}
(mit
α
{\displaystyle {}\alpha }
β
{\displaystyle {}\beta }
γ
{\displaystyle {}\gamma }
0
{\displaystyle {}0}
P
1
,
P
2
,
Q
∈
K
[
T
]
{\displaystyle {}P_{1},P_{2},Q\in K[T]}
Q
≠
0
{\displaystyle {}Q\neq 0}
A
K
1
⊇
D
(
Q
)
⟶
A
K
2
mit
t
⟼
(
P
1
(
t
)
Q
(
t
)
,
P
2
(
t
)
Q
(
t
)
)
{\displaystyle {\mathbb {A} }_{K}^{1}\supseteq D(Q)\longrightarrow {\mathbb {A} }_{K}^{2}\,{\text{ mit }}t\longmapsto \left({\frac {P_{1}(t)}{Q(t)}},{\frac {P_{2}(t)}{Q(t)}}\right)}
in
C
{\displaystyle {}C}
![{\displaystyle {}P_{1},P_{2},Q\in K[T]}](https://wikimedia.org/api/rest_v1/media/math/render/svg/f3cd760802665bd51563149a7217cb57271cd4fa)
