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Publications

In Journals


  1. K. Mahesh Krishna and P. Sam Johnson, “Operator-Valued p-Approximate Schauder Frames”, Journal of the Ramanujan Mathematical Society (accepted for publication).
  2. A. Senthil Thilak, Ayyanar K and P. Sam Johnson, “On the Construction and Properties of Frames Using Incidence Matrix of Graphs and Their Spectra”, Proceedings of the Jangjeon Mathematical Society (accepted for publication).
  3. K. Mahesh Krishna and P. Sam Johnson, “Lipschitz p-Approximate Schauder Frames”, Kragujevac Journal of Mathematics (accepted for publication).
  4. Athira Satheesh K, K. Kamaraj and P. Sam Johnson, “Algebraic Proofs of Characterizing Reverse Order Law for Closed Range Operators in Hilbert Spaces”, Eurasian Mathematical Journal (accepted for publication).
  5. K. Mahesh Krishna and P. Sam Johnson, “Approximately Dual p-Approximate Schauder Frames”, Aust. J. Math. Anal. Appl. 20 (2023), No. 1, Article 22, 9 pages.
  6. K. Kamaraj, P. Sam Johnson and Athira Satheesh K, “Reverse Order Law for Generalized Inverses with Indefinite Hermitian Weights”, Filomat 37:3 (2023), 699-709.
  7. K. Mahesh Krishna and P. Sam Johnson, “Dilations of Linear Maps on Vector Spaces”, Operators and Matrices, Volume 16, Number 2 (2022), 465-477.
  8. P. Sam Johnson, “Closed EP and Hypo-EP Operators on Hilbert Spaces”, The Journal of Analysis (2022) 30:1377-1390.
  9. K. Mahesh Krishna and P. Sam Johnson, “Commutators Close to the Identity in Unital C*-Algebras”, Proceedings - Mathematical Sciences, Vol. 132, Issue 1, June 2022, Article 11, 08 pages.
  10. K. Kamaraj, P. Sam Johnson and Sachin Manjunath Naik, “Generalized Principal Pivot Transform and its Inheritance Properties”, The Journal of Analysis (2022) 30:1241-1256.
  11. Rashid A. and P. Sam Johnson, “P-Operators on Hilbert Spaces”, Palestine Journal of Mathematics, Vol.11 (3) 2022, 85-89.
  12. K. Mahesh Krishna and P. Sam Johnson, “Factorable Weak Operator-Valued Frames”, Annals of Functional Analysis, Vol. 13 (2022) No.1, Article 11, 36 pages.
  13. K. Mahesh Krishna and P. Sam Johnson, “The Noncommutative ℓ1−ℓ2 Inequality for Hilbert C*-Modules and the Exact Constant”, Nonlinear Functional Analysis and Applications, Volume 27, Issue 2, 249-259, 2022.
  14. K. Mahesh Krishna and P. Sam Johnson, “Expansion of Weak Reconstruction Sequences to Approximate Schauder Frames for Banach Spaces”, Asian-European Journal of Mathematics, Vol. 15, No. 3 (2022) 2250060 (6 pages)
  15. K. Mahesh Krishna and P. Sam Johnson, “Frames for Metric Spaces”, Results in Mathematics, Vol. 77, Issue 1, February 2022, Article 49, 30 pages.
  16. K. Mahesh Krishna, P. Sam Johnson and R. N. Mohapatra, “Multipliers for Operator-Valued Bessel Sequences and Generalized Hilbert-Schmidt Classes”, Journal of Applied Mathematics and Informatics, Vol. 40(2022), No. 1-2, pp. 153-171.
  17. K. Mahesh Krishna and P. Sam Johnson, “Dilation Theorem for p-Approximate Schauder Frames for Separable Banach Spaces”, Palestine Journal of Mathematics, Vol.11 (2) 2022, 384-394.
  18. K. Mahesh Krishna and P. Sam Johnson, “Perturbation of p-Approximate Schauder Frames for Separable Banach Spaces”, Poincare Journal of Analysis and Applications, Vol.8, No.1(II) (2021), 15-24.
  19. K. Mahesh Krishna and P. Sam Johnson, “New Identity on Parseval p-Approximate Schauder Frames and Applications”, Journal of Interdisciplinary Mathematics, Vol. 24 (2021), No. 7, 1751–1760.
  20. P. Sam Johnson, Vinoth A and K. Kamaraj, “Fuglede-Putnam Type Commutativity Theorems for EP Operators”, Malaya J. Mat. 9 (2021), No. 1, 709-714.
  21. K. Mahesh Krishna and P. Sam Johnson, “Towards Characterizations of Approximate Schauder Frame and Its Duals for Banach Spaces”, J. Pseudo-Differ. Oper. Appl., 12(1), 2021, Article 9, 13 pages.
  22. Athira Satheesh K, P. Sam Johnson and K. Kamaraj, “Estimates of Norms on Krein Spaces”, Aust. J. Math. Anal. Appl. 17 (2020), No. 2, Article 18, 10 pages.
  23. P. Sam Johnson, “On Semiclosed Operators with Closed Range”, Canad. J. Appl. Math. 2 (2020), No. 2, 18-22.
  24. P. Sam Johnson and S. Balaji, "Convergence of Operators with Closed Range", Khayyam J. Math. 5 (2019) No. 2, 132-138.
  25. Mahesh Krishna and P. Sam Johnson, "Quotient Operators and the Open Mapping Theorem", Filomat 32:18 (2018), 6221-6227.
  26. P. Sam Johnson and Vinoth A, "Product and Factorization of Hypo-EP Operators", Special Matrices 6 (2018), 376-382.
  27. B. Parvathalu and P. Sam Johnson, "Construction of Mercedes-Benz Frame in Rn", International Journal of Applied and Computational Mathematics, December 2017, Issue 1 Supplement, 511-519.
  28. G. Ramu and P. Sam Johnson, "Frames for Operators in Banach Spaces", Acta Mathematica Vietnamica, 42 (2017), 665-673.
  29. Vinoth A and P. Sam Johnson, "On Sum and Restriction of Hypo-EP Operators", Funct. Anal. Approx. Comput. 9 (1) (2017), 37-41.
  30. G. Ramu and P. Sam Johnson, "Frame Operators of K-frames", Boletin de la Sociedad Espanola de Matematica Aplicada, SeMA Journal (2016) 73 : 171-181.
  31. P. Sam Johnson and G. Ramu, "Class of Bounded Operators associated with an Atomic System", Tamkang Journal of Mathematics, Vol.46, No.1, 85-90, March 2015.
  32. P. Sam Johnson, “Multiplication Operators with Closed Range in Operator Algebras", Journal of Analysis and Number Theory, Vol. 1, No.1, 1-5, 2013.
  33. P. Sam Johnson and S. Balaji, “On Semiclosed Subspaces of Hilbert Spaces", International Journal of Pure and Applied Mathematics, Vol. 79, No. 2, 2012, 249-258.
  34. P. Sam Johnson and S. Balaji, “Hyers-Ulam Stability of Linear Operators in Frechet Spaces", Applied Mathematics and Information Sciences, Vol. 6, No.3, 525-528 (2012).
  35. P. Sam Johnson and S. Balaji, “On Linear Operators with Closed Range", Journal of Applied Mathematics and Bioinformatics, Vol.1, No.2, 2011, 175-182.
  36. P. Sam Johnson and C. Ganesa Moorthy, “Composition of Operators with Closed Range", The Journal of Analysis, 14(2006), 79-80.
  37. C. Ganesa Moorthy and P. Sam Johnson, “Composition of Closed Range Operators", The Journal of Analysis, 12(2004), 165-169.

In Conference Proceedings


  1. Vinoth A and P. Sam Johnson, “Factorization of EP Operators in Krein Spaces", Mathematical Analysis and Computing, Springer Proceedings in Mathematics and Statistics, 344, pp. 359-364, 2021. (Proceedings of the International Conference on Mathematical Analysis and Computing held at SSN College of Engineering, Chennai on December 23-24, 2019).
  2. C. Ganesa Moorthy and P. Sam Johnson, “Closed Range - Multiplication Operators", Mathematical Analysis and Applications, Narosa Publishing House, pp 133-138, 2004 (Proceedings of the International Conference on Analysis and Discrete Structures held at Indian Institute of Technology, Kharagpur on December 22-24, 2002).

Papers Submitted


  1. Athira Satheesh K, P. Sam Johnson and K. Kamaraj, “Reverse Order Law for Moore-Penrose Inverse of Closed Operators and its Applications”.
  2. Rahid A and P. Sam Johnson, “On a Sub-class of Matrices Having Convex Sign-reversing Set”.
  3. Sachin Manjunath Naik and P. Sam Johnson, “Schur Complement of Operators on Hilbert Spaces”.
  4. Arup Majumdar, P. Sam Johnson and R. N. Mohapatra, “Hyers-Ulam Stability of Unbounded Closable Operators in Hilbert Spaces”.
  5. K. Mahesh Krishna, P. Sam Johnson and Asghar Rahimi, “Multipliers for Lipschitz p-Bessel Sequences in Metric Spaces”.
  6. Shah Jahan and P. Sam Johnson, “Frame Operators for Frames in Krein Spaces”.
  7. M. Rossafi, F. D. Nhari and P. Sam Johnson, “Controlled Continuous g-Frames and Their Duals in Hilbert Spaces”.