
It is shown that every matrix \(A\in \mathbb{F}^{n\times n}\) over a field \(\mathbb{F}\) of characteristic zero may be represented as \(\lambda_1 Q_1+ \lambda_2 Q_2+ \lambda_3 Q_2\), where \(\lambda_i\in \mathbb{F}\), \(Q_i\in \mathbb{F}^{n\times n}\) and \(Q^2_i= Q_i\). If \(A\in \mathbb{F}^{2\times 2}\) or \(A\in \mathbb{C}^{3\times 3}\) it is fulfilled \(A= \lambda_1 Q_1+ \lambda_2 Q_2\). At the same time there are matrices \(A\in \mathbb{Q}^{3\times 3}\) and \(A\in \mathbb{C}^{4\times 4}\) that are not linear combinations of two idempotents.
Decomposition, Numerical Analysis, Algebra and Number Theory, Idempotent, Linear combination, Matrix equations and identities, Discrete Mathematics and Combinatorics, Geometry and Topology, Factorization of matrices
Decomposition, Numerical Analysis, Algebra and Number Theory, Idempotent, Linear combination, Matrix equations and identities, Discrete Mathematics and Combinatorics, Geometry and Topology, Factorization of matrices
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