Some log-majorizations and an extension of a determinantal inequality

An eigenvalue inequality involving a matrix connection and its dual is established, and some log-majorization type results are obtained. In particular, some eigenvalues inequalities considered by F. Hiai and M. Lin [9], an associated conjecture, and a singular values inequality by L. Zou [20] are revisited. A reformulation of the inequality det(A+U⁎B)≤det(A+B), for positive semidefinite matrices A,B, with U a unitary matrix that appears in the polar decomposition of B A, is also extended, using some known norm inequalities, associated to Furuta inequality and Araki-Cordes inequality.