Indices and nullities of Yang-Mills fields. Proc. Amer. Math. Soc. 98 (1986), no. 3, 475–479. Summary: “In this note, we give an upper estimate of index and nullity of every Yang-Mills field R on every principal bundle P with structure group G over a Riemannian manifold (M, g) with Ricci tensor Ric ≥ kg, k> 0, in terms of dim(M), dim(G), k, and ‖R‖∞.