25:24 To prove AB and BA share the same eigenvalues, I think here the proof only proves the case when B is invertible. So this is not a general proof.####[['AB', 'Mathematical_Related_Concept', 'NEU'], ['BA', 'Mathematical_Related_Concept', 'NEU'], ['eigenvalues', 'Mathematical_Related_Concept', 'NEU'], ['invertible', 'Mathematical_Related_Concept', 'NEU']]