We establish some structural results for the Witt and Grothendieck–Witt groups of schemes over $\mathbb{Z}[1/2]$, including homotopy invariance for Witt groups and a formula for the Witt and Grothendieck–Witt groups of punctured affine spaces over a scheme. All these results hold for singular schemes and at the level of spectra.

中文翻译：

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某些奇异方案的Grothendieck–Witt群

我们为Witt和Grothendieck–Witt方案组建立了一些结构性结果， $\mathbb{ž}[\mathrm{1个}/\mathrm{2个}]$，包括Witt组的同伦不变性，以及方案中Witt和Grothendieck-Witt组被仿射空间的公式。所有这些结果都适用于奇异方案和光谱级别。