On (θ, α)-metric space and fixed point results with application
Abstract
The notion of a double controlled metric type space was introduced by Abdeljawad et al. as a broadening of the controlled metric type spaces of Mlaiki et al., and shortly afterwards Aydi et al. formulated the new extended b-metric spaces to widen the extended b-metric spaces of Kamran et al. Building on these developments, the present work advances the class of (θ, α)-metric spaces, a structure that simultaneously subsumes b-metric spaces, new extended b-metric spaces, controlled metric type spaces and double controlled metric type spaces. This is accomplished by attaching two control functions θ(ζ, µ, s) and α(ζ, µ, s) to the terms situated on the right-hand side of the triangle inequality in the axioms defining a (θ, α)-metric space. We first prove, through explicit propositions, that each of the aforementioned structures is recovered as a special case under an appropriate choice of θ and α, and we supply non-trivial examples confirming that the new class is strictly broader than a b-metric space. Within this setting, a collection of fixed point theorems is derived for φ-contractive and Reich–Ćirić–Rus–type operators, together with their corollaries. Finally, two applications are presented: the principal theorem is first used to guarantee that a nonlinear algebraic equation possesses a unique solution, and it is then applied to establish the existence and uniqueness of a solution to a nonlinear Caputo fractional boundary value problem, thereby strengthening the connection of the theory with differential equations.
Copyright (c) 2026 Mohammad Akram, Umar Ishtiaq, Zainab Bibi, Tayyab Kamran, Ioan-Lucian Popa

This work is licensed under a Creative Commons Attribution 4.0 International License.
References
[1]Banach S. Sur les opérations dans les ensembles abstraits et leur application aux équations intégrales. Fundamenta
[2]Mathematicae. 1922; 3: 133–181.
[3]Bakhtin IA. The contraction mapping principle in almost metric spaces. Functional Analysis. 1989; 30: 26–37.
[4]Czerwik S. Contraction mappings in b-metric spaces. Acta Mathematica et Informatica Universitatis Ostraviensis.
[5]; 1: 5–11.
[6]Huang H, Deng G, Radenović S. Fixed point theorems in b-metric spaces with applications to differential equations.
[7]Journal of Fixed Point Theory and Applications. 2018; 20(1): 52. doi: 10.1007/s11784-018-0491-z
[8]Rezaei Roshan J, Parvaneh V, Sedghi S, et al. Common fixed points of almost generalized (ψ, φ)s-contractive
[9]mappings in ordered b-metric spaces. Fixed Point Theory and Applications. 2013; 2013(1): 159. doi:
[10]1186/1687-1812-2013-159
[11]Mukheimer A, Mlaiki N, Abodayeh K, et al. New theorems on extended b-metric spaces under new contractions.
[12]Nonlinear Analysis: Modelling and Control. 2019; 24(6). doi: 10.15388/NA.2019.6.2
[13]Shatanawi W, Pitea A, Lazović R. Contraction conditions using comparison functions on b-metric spaces. Fixed Point
[14]Theory and Applications. 2014; 2014(1): 135. doi: 10.1186/1687-1812-2014-135
[15]Younis M, Singh D, Shi L. Revisiting graphical rectangular b-metric spaces. Asian-European Journal of Mathematics.
[16]; 15(4): 2250072. doi: 10.1142/S1793557122500723
[17]Abdeljawad T, Abodayeh K, Mlaiki N. On fixed point generalizations to partial b-metric spaces. Journal of
[18]Computational Analysis and Applications. 2015; 19(5): 883–891.
[19]Shatanawi W, Mustafa Z, Tahat N. Some Coincidence Point Theorems for Nonlinear Contraction in Ordered Metric
[20]Spaces. Fixed Point Theory and Applications. 2011; 2011(1): 68. doi: 10.1186/1687-1812-2011-68
[21]Rasham T, Shabbir MS, Agarwal P, et al. On a pair of fuzzy dominated mappings on closed ball in the multiplicative
[22]metric space with applications. Fuzzy Sets and Systems. 2022; 437: 81–96. doi: 10.1016/j.fss.2021.09.002
[23]Gupta V, Gondhi A. Fixed points of weakly compatible maps on modified intuitionistic fuzzy soft metric spaces. International Journal of System Assurance Engineering and Management. 2022; 13(3): 1232–1238. doi:
[24]1007/s13198-021-01423-1
[25]Gupta V, Mani N, Sharma R, et al. Some fixed point results and their applications on integral type contractive condition
[26]in fuzzy metric spaces. Boletim da Sociedade Paranaense de Matemática. 2022; 40: 1–9. doi: 10.5269/bspm.51777
[27]Chauhan SS, Gupta V. Banach contraction theorem on fuzzy cone b-metric space. Journal of Applied Research and
[28]Technology. 2020; 18(4): 154–160. doi: 10.22201/icat.24486736e.2020.18.4.1188
[29]Gamal M, Rasham T, Cholamjiak W, et al. New iterative scheme for fixed point results of weakly compatible
[30]maps in multiplicative GM−metric space via various contractions with application. AIMS Mathematics. 2022; 7(8):
[31]–13703. doi: 10.3934/math.2022754
[32]Rasham T, Nazam M, Aydi H, et al. Hybrid pair of multivalued mappings in modular-like metric spaces and
[33]applications. AIMS Mathematics. 2022; 7(6): 10582–10595. doi: 10.3934/math.2022590
[34]Younis M, Singh D, Chen L, et al. A study on the solutions of notable engineering models. Mathematical Modelling
[35]and Analysis. 2022; 27(3): 492–509. doi: 10.3846/mma.2022.15276
[36]Kamran T, Samreen M, Ul Ain Q. A Generalization of b-Metric Space and Some Fixed Point Theorems. Mathematics.
[37]; 5(2): 19. doi: 10.3390/math5020019
[38]Mlaiki N, Aydi H, Souayah N, et al. Controlled Metric Type Spaces and the Related Contraction Principle. Mathematics.
[39]; 6(10): 194. doi: 10.3390/math6100194
[40]Aiadi SS, Othman WAM, Wong KB, et al. Fixed point theorems in controlled J−metric spaces. AIMS Mathematics.
[41]; 8(2): 4753–4763. doi: 10.3934/math.2023235
[42]Ahmad H, Younis M, Köksal ME. Double Controlled Partial Metric Type Spaces and Convergence Results. Journal
[43]of Mathematics. 2021; 2021: 1–11. doi: 10.1155/2021/7008737
[44]Rasham T, Shoaib A, Alshoraify S, et al. Study of multivalued fixed point problems for generalized contractions
[45]in double controlled dislocated quasi metric type spaces. AIMS Mathematics. 2021; 7(1): 1058–1073. doi:
[46]3934/math.2022063
[47]Rezazgui AZ, Tallafha AA, Shatanawi W. Common fixed point results via Aϑ-α-contractions with a pair and two pairs
[48]of self-mappings in the frame of an extended quasi b-metric space. AIMS Mathematics. 2023; 8(3): 7225–7241. doi:
[49]3934/math.2023363
[50]Souayah N, Hidri L. New Fixed-Point Results in Controlled Metric Type Spaces with Applications. Axioms. 2025;
[51](2): 85. doi: 10.3390/axioms14020085
[52]Shammaky AE, Ahmad J. Common Fixed Point Theorems in Complex-Valued Controlled Metric Spaces with
[53]Application. Symmetry. 2024; 16(11): 1442. doi: 10.3390/sym16111442
[54]Abdeljawad T, Mlaiki N, Aydi H, et al. Double Controlled Metric Type Spaces and Some Fixed Point Results.
[55]Mathematics. 2018; 6(12): 320. doi: 10.3390/math6120320
[56]Bostan NU, Pazar Varol B. Fixed Point Results in Modular b-Metric-like Spaces with an Application. Axioms. 2024;
[57](10): 726. doi: 10.3390/axioms13100726
[58]Middlebrook C, Feng W. Integral Operators in b-Metric and Generalized b-Metric Spaces and Boundary Value
[59]Problems. Fractal and Fractional. 2024; 8(11): 674. doi: 10.3390/fractalfract8110674
[60]Mebarki K, Boudaoui A, Belhenniche A, et al. Fixed-Point Theorems for Covariant and Contravariant Multivalued
[61]Mappings in Bipolar b-Metric Spaces. Mathematics. 2025; 13(18): 2983. doi: 10.3390/math13182983
[62]Aydi H, Felhi A, Kamran T, et al. On nonlinear contractions in new extended b-metric spaces. Applications and Applied
[63]Mathematics. 2019; 14(1): 537–547.
[64]Rhoades BE. Some theorems on weakly contractive maps. Nonlinear Analysis: Theory, Methods & Applications.
[65]; 47(4): 2683–2693. doi: 10.1016/S0362-546X(01)00388-1
[66]Karapinar E, Petrusel A, Petrusel G. On admissible hybrid Geraghty contractions. Carpathian Journal of Mathematics.
[67]; 36(3): 433–442. doi: 10.37193/CJM.2020.03.11
[68]Shatanawi W, Abodayeh K, Mukheimer A. Some fixed point theorems in extended b-metric spaces. UPB Scientific
[69]Bulletin, Series A: Applied Mathematics and Physics. 2018; 80(4): 71–78.
[70]Alamri B. Fixed Point Results in Extended ℱ-Metric Spaces with Applications to Caputo Fractional Differential
[71]Equations. Fractal and Fractional. 2026; 10(4): 261. doi: 10.3390/fractalfract10040261
[72]Alfaqih WM, Sessa S, Saleh HN, et al. Solving Fractional Differential Equations via New Relation-Theoretic Fuzzy
[73]Fixed Point Theorems. Mathematics. 2025; 13(16): 2582. doi: 10.3390/math13162582
[74]Erkan F, Hamal NA, Ntouyas SK, et al. Existence and Uniqueness Analysis for (k, ψ)-Hilfer and (k, ψ)-Caputo
[75]Sequential Fractional Differential Equations and Inclusions with Non-Separated Boundary Conditions. Fractal and Fractional. 2025; 9(7): 437. doi: 10.3390/fractalfract9070437
[76]Alharbi N, Hussain N, Alsulami H. Efficient Fixed-Point Method with Application to a Fractional Blood Flow Model.
[77]Fractal and Fractional. 2025; 9(11): 752. doi: 10.3390/fractalfract9110752




