A formula for the $g$-angle between two subspaces of a normed space

We develop the notion of $g$-angle between two subspaces of a normed space. In particular, we discuss the $g$-angle between a $1$-dimensional subspace and a $t$-dimensional subspace for $t\geq 1$ and the $g$-angle between a $2$-dimensional subspace and a $t$-dimensional subspace for $t\geq 2$. Moreover, we present an explicit formula for the $g$-angle between two subspaces of $\ell^{p}$ spaces.