Let G be a connected graph of order n. A P2, C3, P5, T (3) -factor of G is a spanning subgraph of G such that each component is isomorphic to a member in P2, C3, P5, T (3), where T (3) is a 1, 2, 3-tree. The A? -spectral radius of G is denoted by? ? (G). In this paper, we obtain a lower bound on the size or the A? -spectral radius for? ? [0, 1) of G to guarantee that G has a P2, C3, P5, T (3) -factor, and construct an extremal graph to show that the bound on A? -spectral radius is optimal.
Zhang et al. (2025) studied this question.