Johnson, P.S.2026-02-042022Journal of Analysis, 2022, 30, 4, pp. 1377-13909713611https://doi.org/10.1007/s41478-022-00401-5https://idr.nitk.ac.in/handle/123456789/22304A bounded linear operator A on a Hilbert space H is said to be an EP (hypo-EP) operator if ranges of A and A∗ are equal (range of A is contained in range of A∗) and A has a closed range. In this paper, we define EP and hypo-EP operators for densely defined closed linear operators on Hilbert spaces and extend results from bounded linear operator settings to (possibly unbounded) closed linear operator settings. © 2022, The Author(s), under exclusive licence to The Forum D’Analystes.EP operatorHypo-EP operatorMoore-Penrose inverse