矩阵求逆引理
若矩阵A∈CN×NA \in C^{N \times N}A∈CN×N,C∈CM×MC\in C^{M \times M}C∈CM×M,均为非奇异矩阵,矩阵B∈CN×MB\in C^{N \times M}B∈CN×M,D∈CM×ND\in C^{M \times N}D∈CM×N,则矩阵A+BCD具有逆矩阵:
(A+BCD)−1=A−1−A−1B(DA−1B+C−1)−1DA−1
(A+BCD)^{-1}=A^{-1}-A^{-1}B(DA^{-1}B+C^{-1})^{-1}DA^{-1}
(A+BCD)−1=A−1−A−1B(DA−1B+C−1)−1DA−1