Irregularity of a product of curves
= Irregularity of a product of curves
For smooth projective curves $C$ and $D$, the <Künneth theorem> gives
$$
q(C\times D)=g(C)+g(D).
$$
= Irregularity of a product of curves
For smooth projective curves $C$ and $D$, the <Künneth theorem> gives
$$
q(C\times D)=g(C)+g(D).
$$