grandes-ecoles 2019 Q1

grandes-ecoles · France · centrale-maths1__pc Matrices Structured Matrix Characterization

Are the subsets $\mathrm{T}_{n}(\mathbb{K})$ and $\mathrm{T}_{n}^{+}(\mathbb{K})$ subalgebras of $\mathcal{M}_{n}(\mathbb{K})$?

Are the subsets $\mathrm{T}_{n}(\mathbb{K})$ and $\mathrm{T}_{n}^{+}(\mathbb{K})$ subalgebras of $\mathcal{M}_{n}(\mathbb{K})$?