$\DeclareMathOperator{\Spec}{Spec}$
Hello everybody.
Im sorry if this is a stupid question, but I don't know the answer myself and would like to know it.
What does the notation $\mathbb{P}_{a,b}^1$ mean?
I saw this for the first time in the Wikipedia article about $\Spec(-)$ in the section about global $\Spec(-)$. I couldn't find this notation anywhere else.
Thank You for Your help,
kindly SDIGR