P. Sam Johnson

Designation: 

Professor
Contact Details

E-mail: 

sam[at]nitk.edu.in
nitksam[at]gmail.com

Telephone: 

91-824-2473361

Mobile: 

094488 45980

Personal Website: 

http://sam.nitk.ac.in

Google Scholar: 

https://scholar.google.com/citations?user=krPYVDwAAAAJ&hl=en
Faculty (author) Identifiers

ORCID iD: 

https://orcid.org/my-orcid?orcid=0000-0003-3461-5380

Scopus Author ID: 

https://www.scopus.com/authid/detail.uri?authorId=57226629182

WoS Researcher ID: 

https://www.webofscience.com/wos/author/record/1645571

Research Gate: 

https://www.researchgate.net/profile/P-Johnson?ev=hdr_xprf

MathSciNet: 

https://mathscinet.ams.org/mathscinet/author?authorId=761533
Academic Background
  • PhD, Alagappa University, 2005
  • MPhil, Alagappa University, 2001
  • MSc, Alagappa University, 2000
  • BSc, Madurai Kamaraj University, 1998
Areas of Interest
  • Functional Analysis
  • Operator Theory
Significant Projects
 
  • Funding Agency: SERB, Government of India, under the scheme MATRICS (MTR/2023/000471) ; Title of the Project: Hyers-Ulam Stability of Unbounded Operators and C₀-Semigroup Operators ; Duration: Three years from 21.12.2023 to 20.12.2026; On-going.
  • Funding Agency: NBHM, DAE, Government of India NBHM/2023/R&D-II/5947 ; Title of the Project: Hyers-Ulam Stability of Frames and Operators in Hilbert Spaces ; Duration: Three  years from 04.05.2023 to 03.05.2026; On-going. 
  • Funding Agency:TARE Fellowship Grant, SERB, DST, Government of India (AR/2022/000219) ; Title of the Project: A Study of Frames for Operators in Hilbert Spaces ; Duration: Three years from 18.10.2022 to 17-10-2025; Completed.
  • Funding Agency: SERC, DST, Government of India SR/FTP/ MS-050/2011 ; Title of the Project: Topological Structures  for Semiclosed Operators on Hilbert spaces ; Duration: Three  years from 17.05.2014 to 16.05.2017 ; Completed.
  • Funding Agency: NBHM, DAE, Government of India NBHM/R.P.45/2012/Fresh/308 ; Title of the Project: A Study on Moore-Penrose Inverses in Krein spaces; Duration: Three  years from 15.08.2013 to 14.08.2016 ; Completed.
  • Funding Agency: NITK, Surathkal ; RGO/O.M/SEED GRANT/106/2009 ; Title of the Project : A Study on Closed Range Operators; Duration : Two years  from 26.01.2009 to 25.01.2011 ; Completed.
Supervision of Ph.D
Awarded: 08, Submitted: 01, Ongoing: 03
 
Current Students
1. Shashank S
2. Mohana K.S.
3. Thinkal V
 
Degree Awarded
1. S. Balaji (2014) : A Study on Semiclosed Subspaces and Semiclosed Operators in Hilbert Spaces
2. G. Ramu (2017) : Frames for Operators in Hilbert and Banach Spaces
3. Vinoth A. (2020) : A Study on EP and Hypo-EP Operators
4. Mahesh Krishna K. (2022) : Metric, Schauder and Operator-Valued Frames
5. Athira Satheesh (2024) : Reverse Order Law for Moore-Penrose Inverse in Hilbert and Indefinite Inner Product Spaces
6. Rashid A (2024) : A Study on Certain Positivity Classes of Operators in Hilbert Spaces
7. Sachin Manjunath Naik (2025) : Complementable Operators and Their Schur Complements in Hilbert Spaces
8. Arup Majumdar (2025) : A Study of Closable Operators in Hilbert Spaces and the Spectral Analysis in Semi-Hilbertian Spaces
 
Achievements
Organization of Conferences and other Academic Events
• Organized a national-level workshop on "Functional Analysis and Operator Algebras (FAOA-2026)" sponsored by ANRF during 01-05, June 2026.
• Organized a national-level seminar on the occasion of "National Mathematics Day" on 22 December 2024 (Commemorating the 138th birth anniversary of one of the greatest Indian mathematicians, Srinivasa Ramanujan). 
• Organized a national-level seminar on the occasion of "National Mathematics Day" on 22 December 2023 (Commemorating the 137th birth anniversary of one of the greatest Indian mathematicians, Srinivasa Ramanujan).  
• Organized a national-level seminar on the occasion of "National Mathematics Day" on 22 December 2022 (Commemorating the 136th birth anniversary of one of the greatest Indian mathematicians, Srinivasa Ramanujan). 
• Organized a national-level workshop on "Topological Dynamics" sponsored by NBHM during 10-12, December 2015. 
• Organized a national-level workshop on "Functional Analysis and Operator Algebras" sponsored by NBHM during 02-07, June 2014. 
• Organized a national-level workshop on "Spectral Analysis and Applications" sponsored by NBHM during 14-16, February 2013. 
• Invited Talks Arranged in MACS Department : 17
 
Awards and Distinctions 
• Received Merit Scholarship from Alagappa University in M.Phil.
• Alagappa University Second Rank in M.Phil.
• Qualified National Eligiblity Test (NET-JRF) conducted by CSIR
• Received Junior Research Fellowship (JRF) from CSIR while doing Ph.D
 
Assignments/Responsibilities
• Head - Department of MACS, 2023-2025
• Associate Dean - Faculty Welfare, 2021-2023
• Treasurer of Staff Recreation Club (SRC) at NITK, 2021-2023
• Faculty In-charge (Security), 2016-2018
• Member of Institute Grievance Redressal Committee, 2015-2020
• Visiting Faculty to IIIT Dharwad, 2015
• Associate NCC Officer (ANO) at NITK, 2012-2026
Visits Abroad

Canada (2013), Egypt (2011), Italy (2024), Malaysia (2008, 2010), South Korea (2014), Spain (2024), United Kingdom (2017), United States of America (2014, 2023).

Significant Publications
  1. Rashid A. and P. Sam Johnson, “Sign Reversing Set of Operators on Hilbert Spaces”, Periodica Mathematica Hungarica (accepted).
  2. Arup Majumdar, P. Sam Johnson and Ram N. Mohapatra, “Characterizations of Closed EP Operators on Hilbert Spaces”,  Operators and Matrices, Volume 20, Number 2 (2026), 129-145.
  3. Sachin Manjunath Naik and P. Sam Johnson, “On Unbounded Complementable Operators”, Advances in Operator Theory, Volume 11, Article Number 42 (2026).
  4. Arup Majumdar, P. Sam Johnson and Ram N. Mohapatra, “On the Generalized Cauchy Dual of Closed Operators in Hilbert Spaces”, Acta Scientiarum Mathematicarum, Volume 92, pages 69-89 (2026).
  5. Rashid A. and P. Sam Johnson, “Some Spectral Results for Certain Positive Operators in Hilbert Spaces”, Methods of Functional Analysis and Topology, Volume 32 (2026), Number 1, pages 84-96.
  6. K. Mahesh Krishna, P. Sam Johnson and Harikrishnan Panackal, “Multipliers for Lipschitz p-Bessel Sequences in Metric Spaces”, Nonlinear Functional Analysis and Applications, Volumber 30, Number 4 (2025), pages 1187-1203.
  7. Mohamed Rossafi, Fakhr-Dine Nhari and P. Sam Johnson, “Controlled Continuous g-Frames and Their Duals in Hilbert Spaces”, Palestine Journal of Mathematics, Volume 15 (2026), Number 1, pages 21-31.
  8. K. Kamaraj, A. Karpagam and P. Sam Johnson, “Canonical Representations of Space, Diamond and Plus Matrix Partial Orders in an Indefinite Inner Product Space”, The Journal of Analysis, Volume 34, pages 1367-1385 (2026).
  9. K. Mahesh Krishna and P. Sam Johnson, “Lipschitz p-Approximate Schauder Frames”, Kragujevac Journal of Mathematics, Volume 50, Number 2 (2026), pages 217-230.
  10. Sachin Manjunath Naik and P. Sam Johnson, “Convergence of Complementable Operators”, Linear Algebra and its Applications, Volume 719, 15 August 2025, Pages 66-92.
  11. Athira Satheesh K, P. Sam Johnson and K. Kamaraj, “Reverse Order Law for Moore-Penrose Inverse of Closed Operators and its Applications”, Indian Journal of Pure and Applied Mathematics, 56(2), 1026-1035 (2025). 
  12. Sachin Manjunath Naik and P. Sam Johnson, “Complementable Operators and their Schur Complements”, Indian Journal of Pure and Applied Mathematics, 56(2), 1131-1143 (2025).
  13. Arup Majumdar and P. Sam Johnson, “A-Approximate Point Spectrum of A-Bounded Operators in Semi-Hilbertian Spaces”, Indian Journal of Pure and Applied Mathematics, 56(2), 1163-1176 (2025). 
  14. Shah Jahan and P. Sam Johnson, “Riesz Bases in Krein Spaces”, Indian Journal of Pure and Applied Mathematics, 56(2), 1005-1013 (2025). 
  15. Ayyanar K, P. Sam Johnson and A. Senthil Thilak, “Frame Scaling by Graphs”, Indian Journal of Pure and Applied Mathematics, 56(2), 891-900 (2025). 
  16. Hemalatha M, P. Sam Johnson, and Harikrishanan P.K. “Direct Sum of Lower Semi-frames in Hilbert Spaces”, Gulf Journal of Mathematics, 19(2), 412-423, 2025.
  17. Arup Majumdar and P. Sam Johnson, “The Moore-Penrose Inverses of Unbounded Closable Operators and the Cartesian Product of Closed Operators in Hilbert Spaces”, Linear and Multilinear Algebra, 73(8), 1668-1684 (2025). 
  18. 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, 27 (2024), No. 4, pp. 549 - 564. 
  19. Arup Majumdar, P. Sam Johnson and Ram N. Mohapatra, “Hyers-Ulam Stability of Unbounded Closable Operators in Hilbert Spaces”, Mathematische Nachrichten, 297, No.10 (2024), 3887-3903. 
  20. Shah Jahan and P. Sam Johnson, “Frame Operators for Frames in Krein Spaces”, European Journal of Mathematical Analysis, 4 (2024), Article 1 (10 pages). 
  21. K. 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. Mahesh Krishna and P. Sam Johnson, “Operator-Valued p-Approximate Schauder Frames”, J. Ramanujan Math. Soc. 38, No.3 (2023), 369-392. 
  22. 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, Volume 14, Number 3 (2023), 08-25. 
  23. 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. 
  24. 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.
  25. Ameya Vyas and P. Sam Johnson, “Anomaly Detection in Electric Powertrain System Software Behaviour", Published in: 14th International Conference on Computing Communication and Networking Technologies (ICCCNT), 06-08 July 2023, Delhi (Publisher: IEEE). 
  26. K. Mahesh Krishna and P. Sam Johnson, “Dilations of Linear Maps on Vector Spaces”, Operators and Matrices, Volume 16, Number 2 (2022), 465-477. 
  27. P. Sam Johnson, “Closed EP and Hypo-EP Operators on Hilbert Spaces”, The Journal of Analysis (2022) 30:1377-1390. 
  28. 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.
  29. 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. 
  30. Rashid A. and P. Sam Johnson, “P-Operators on Hilbert Spaces”, Palestine Journal of Mathematics, Vol.11 (3) 2022, 85-89.
  31. 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. 
  32. 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. 
  33. 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).
  34. K. Mahesh Krishna and P. Sam Johnson, “Frames for Metric Spaces”, Results in Mathematics, Vol. 77, Issue 1, February 2022, Article 49, 30 pages. 
  35. K. Mahesh Krishna, P. Sam Johnson and Ram 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. 
  36. 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. 
  37. 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. 
  38. 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. 
  39. 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. 
  40. 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.
  41. 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.
  42. 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.
  43. P. Sam Johnson, “On Semiclosed Operators with Closed Range”, Canad. J. Appl. Math. 2 (2020), No. 2, 18-22. 
  44. P. Sam Johnson and S. Balaji, "Convergence of Operators with Closed Range", Khayyam J. Math. 5 (2019) No. 2, 132-138. 
  45. Mahesh Krishna and P. Sam Johnson, "Quotient Operators and the Open Mapping Theorem", Filomat 32:18 (2018), 6221-6227.
  46. P. Sam Johnson and Vinoth A, "Product and Factorization of Hypo-EP Operators", Special Matrices 6 (2018), 376-382. 
  47. 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. 
  48. G. Ramu and P. Sam Johnson, "Frames for Operators in Banach Spaces", Acta Mathematica Vietnamica, 42 (2017), 665-673. 
  49. Vinoth A and P. Sam Johnson, "On Sum and Restriction of Hypo-EP Operators", Funct. Anal. Approx. Comput. 9 (1) (2017), 37-41. 
  50. 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.
  51. 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. 
  52. P. Sam Johnson, “Multiplication Operators with Closed Range in Operator Algebras", Journal of Analysis and Number Theory, Vol. 1, No.1, 1-5, 2013. 
  53. 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. 
  54. 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). 
  55. 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.
  56. P. Sam Johnson and C. Ganesa Moorthy, “Composition of Operators with Closed Range", The Journal of Analysis, 14(2006), 79-80. 
  57. C. Ganesa Moorthy and P. Sam Johnson, “Closed Range - Multiplication Operators", Mathematical Analysis and Applications, Narosa Publishing House, pp 133-138, 2004.
  58. C. Ganesa Moorthy and P. Sam Johnson, “Composition of Closed Range Operators", The Journal of Analysis, 12(2004), 165-169.
     
Remarks

Detailed CV: 

https://macs.l3.nitk.ac.in/sites/default/files/uploads/Sam-CV_2.pdf
 

Contact us

Dr. Pushparaj Shetty D , Professor and Head
Department of Mathematical and Computational Sciences,
NITK, Surathkal
P. O. Srinivasnagar, Mangalore - 575 025
Karnataka, India.

  • Hot line: +91-0824-2474032

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