George, S.Sadananda, R.Padikkal, J.Kunnarath, A.Argyros, I.K.2026-02-042024Mathematics, 2024, 12, 15, pp. -https://doi.org/10.3390/math12152377https://idr.nitk.ac.in/handle/123456789/20981Tautenhahn (2002) studied the Lavrentiev regularization method (LRM) to approximate a stable solution for the ill-posed nonlinear equation (Formula presented.), where (Formula presented.) is a nonlinear monotone operator and X is a Hilbert space. The operator in the example used in Tautenhahn’s paper was not a monotone operator. So, the following question arises. Can we use LRM for ill-posed nonlinear equations when the involved operator is not monotone? This paper provides a sufficient condition to employ the Lavrentiev regularization technique to such equations whenever the operator involved is non-monotone. Under certain assumptions, the error analysis and adaptive parameter choice strategy for the method are discussed. Moreover, the developed theory is applied to two well-known ill-posed problems—inverse gravimetry and growth law problems. © 2024 by the authors.adaptive parameter choiceill-posed nonlinear equationiterative methodlavrentiev regularizationnon-monotone operator