Notation: In the following questions, underlined letters such as g, b, etc. denote column vectors of proper length； boldface letters such as A, B, etc. denote matrices of proper size； means the transpose of matrix A. is the (n x n) identity matrix. ||αl| means the Euclidean norm of vector @. R is the usual set of all real nun det
(A) is the determinant of square matrix A. row
(A) and col
(A) are the row and column spaces of A over R, respectively. For any linear map T over vector spaces, we use ker(T), rank(T') and nullity(T) for the kernel, rank and nullity of T, respectively. Let W be a subspace of , then by W ┴ we mean the orthogonal complement of W in the Euclidean inner product space denote the   unilateral   Laplace and inverse Laplace transforms for t 2 0, respectively.