So the entries of the one by two matrix describing the projection transformation are going to be the coordinates of you hat.

所以这个1×2矩阵的元素描述了这个投影变换就是这个帽子的坐标。

And computing this projection transformation for arbitrary vectors in space, which requires multiplying that matrix by those vectors, is computationally identical to taking a dot product with you hat.

计算空间中任意向量的投影变换 需要用这些向量乘以这个矩阵 在计算上和做点积是一样的。