Gromov width of the monotone product of projective lines
= Gromov width of the monotone product of projective lines
{c}
{title2=$c_G(\mathbb{CP}^1\times\mathbb{CP}^1)=\pi$}
When each projective line has area $\pi$, the product $\mathbb{CP}^1\times\mathbb{CP}^1$ has Gromov width $\pi$. The lower bound comes from the product of two area-$\pi$ discs; the upper bound comes from a J-holomorphic sphere of area $\pi$ through the center of any proposed ball.