My question has been answered positiv by David B. Leep in his publication
The u-invariant of p-adic function fields - Journal für die reine und angewandte Mathematik, Band 2013, Heft 679 (Jun 2013).
My question has been answered positiv by David B. Leep in his publication
The u-invariant of p-adic function fields - Journal für die reine und angewandte Mathematik, Band 2013, Heft 679 (Jun 2013).