Eigenvalues and eigenvectors - Wikipedia
https://en.wikipedia.org/wiki/Eigenvalues_and_eigenvectorsIf T is a linear transformation from a vector space V over a field F into itself and v is a nonzero vector in V, then v is an eigenvector of T if T(v) is a scalar multiple of v. This can be written as where λ is a scalar in F, known as the eigenvalue, characteristic value, or characteristic root associated with v. There is a direct correspondence between n-by-n square matricesand linear transformations fro…