grandes-ecoles 2018 QI.1

grandes-ecoles · France · x-ens-maths__pc Matrices Combinatorial Structures on Permutation Matrices/Groups
What is the cardinality of $\mathcal{M}_{n}(\{-1,1\})$? Is this set a vector subspace of $\mathcal{M}_{n}(\mathbb{R})$? 
What is the cardinality of $\mathcal{M}_{n}(\{-1,1\})$? Is this set a vector subspace of $\mathcal{M}_{n}(\mathbb{R})$?
Paper Questions
QI.1 QI.2 QI.3 QI.4 QI.5 QI.6 QII.1 QII.2 QII.3 QII.4 QII.5 QII.6 QIII.1 QIII.2 QIII.3 QIII.4 QIV.1 QIV.2 QIV.3 QIV.4 QV.1 QV.2