noun
identity matrix; unit matrix
A square matrix with ones on the main diagonal and zeros elsewhere; the multiplicative identity in matrix algebra.
単位行列は、任意の行列に掛けても元の行列が得られる。
Multiplying any matrix by the identity matrix yields the original matrix.
Compound of 単位 (unit) and 行列 (matrix), reflecting the matrix's role as the multiplicative unit in matrix algebra.