Gribov's horizon and the ghost dressing function

Understand

We study a relation recently derived by K.

• Kondo at zero momentum between the Zwanziger's horizon function, the ghost dressing function and Kugo's functions $u$ and $w$.
• We agree with this result as far as bare quantities are considered.
• However, assuming the validity of the horizon gap equation, we argue that the solution $w(0)=0$ is not acceptable since it would lead to a vanishing renormalised ghost dressing function.