In 1965, Zadeh [3] coined the term "fuzzy set." Following that, a slew of authors worked on fuzzy sets, expanding the fuzzy set theory and its applications [4][5][6]. The idea of fuzzy metric spaces was given by Kramosil and Michalik [7]. After then, George and Veeramani [9] updated this idea. Grabiec [8] investigated fuzzy metric space fixed-point theory. The idea of complex-valued metric spaces was introduced by Azam et al. [21].
Verma et al. [23] recently established 'Max' functions and the partial order relation'for complex numbers, and used properties (E-A) and CLRg to prove fixed point theorems in complex valued metric space. Singh et al. [25] were the first to present the concept of complex-valued fuzzy metric spaces and to create the complex-valued fuzzy version of some metric space results.
The goal of this study is to expand well-known metric-space results to complex-valued fuzzy metric spaces and then prove them in complex-valued complete fuzzy metric spaces.
Def.2.1. [21]. Let ? be the set of complex numbers and ? 1 , ? 2 ? ?, where ? = ? + ??. Then a partial order relation '? ' on ? is defined as follows:
? 1 ? ? 2 â??" ??(? 1 ) ? ??(? 2 ) and ??(? 1 ) ? ??(? 2 )Hence ? 1 ? ? 2 if one of the following satisfies;
London Journal of Research in Science: Natural and Formal (PO1) ??(? 1 ) = ??(? 2 ) and ??(? 1 ) = ??(? 2 ) (PO2) ??(? 1 ) < ??(? 2 ) and ??(? 1 ) = ??(? 2 ) (PO3) ??(? 1 ) = ??(? 2 ) and ??(? 1 ) < ??(? 2 ) (PO4) ??(? 1 ) < ??(? 2 ) and ??(? 1 ) < ??(? 2 )
In particular, ? 1 ? ? 2 if ? 1 ? ? 2 and one of (PO2), (PO3), and (PO4) is satisfied, and we write ? 1 ? ? 2 if only (PO4) is satisfied.
It can be noted that;
0 ? ? 1 ? ? 2 ? |? 1 | < |? 2 |, ? 1 ? ? 2 , ? 2 ? ? 3 ? ? 1 ? ? 3 . Def.2.2.[21]. Complex-Valued Metric Space (CVMS)Let ? be a non-empty set. Assume that the mappings ?: ? × ? ? ? satisfies: (CV1) 0 ? ?(?, ?), for all ?, ? ? ? and ?(?, ?) = 0 iff ? = ? ;
(CV2) ?(?, ?) = ?(?, ?), for all ?, ? ? ? ;
(CV3) ?(?, ?) ? ?(?, ?) + ?(?, ?), for all ?, ?, ? ? ? Then ? is called a complex-valued metric on ?, and (?, ?) is called a CVMS. Def.2.3. [23]. The 'max' function with partial order relation '?' is defined as
(1) ??? {? 1 , ? 2 } = ? 2 â??" ? 1 ? ? 2 (2) ? 1 ? ??? {? 2 , ? 3 } ? ? 1 ? ? 2 or ? 1 ? ? 3And the 'min' functions can be defined as
(1) ??? {? 1 , ? 2 } = ? 1 â??" ? 1 ? ? 2 (2) ??? {? 1 , ? 2 } ? ? 3 ? ? 1 ? ? 3 or ? 2 ? ? 3 .Following Zadeh's [3] contribution to fuzzy set theory, a number of scholars [4][5][6] contributed to the field's basics and core theories.
Buckley [10] was the first to present the concept of fuzzy complex numbers. Other authors were inspired by Buckley's work and continued their research on fuzzy complex numbers. Ramot et al. [1] expanded fuzzy sets to complex fuzzy sets in this chain.
] constructed complex-valued fuzzy metric spaces using continuous t -norms, defined a Hausdorff topology on complex -valued fuzzy metric space, and gave the concept of Cauchy sequences in CVFMS.
We establish certain fixed-point conclusions in the situation of complex -valued fuzzy metric spaces, inspired by Singh et al. [25]. We begin by extending several well-known metric-space results to complex-valued fuzzy metric spaces, and then we prove those results in the setting of CVFMS. Def.2.4. [1]. The complex fuzzy set ? is given by ? = {(?, ? ? (?)) ? ? ? ?}.
Where ? is a universe of discourse, ? ? (?) is a membership function and defined as ? ? (?) = ? ? (?). ? ?? ? (?) The triplet (?, ?, * ) is said to be CVFMS if a complex valued fuzzy set ? ? ? × ? × (0, ?) ? ? ? ? ?? (where ? ? ?, * is a complex valued continuous t-norm) fulfil the following criteria: and ? > 0. Let ?: ? ? ? be a mapping that satisfies ?(??, ??, ??) ? ?(?, ?, ?), ? ? ? (0, 1). Then ? has a fixed point that is unique.
Fisher [24] established the following theorem in complete metric space for three mappings.
Theorem A [24]. Let S and T be continuous mappings of a complete metric space (X, d) into themselves. Then S and T have a common fixed point in X iff a continuous mapping A of X into S(X) ?T(X) exists, which commutes with S and T and satisfies;
?(??, ??) ? ? ?(??, ??) for all ?, ? ? ? and 0 < ? < 1. Indeed ?, ? and ? have a unique common fixed point.
We can now extend the preceding theorem/result to complex-valued complete fuzzy metric space as follows:
Theorem -3.1. Let (?, ?, * ) be a complex-valued complete fuzzy metric space (CVCFMS). ? and ? are continuous mappings from ? to ?. If ? is a continuous mapping from ? to ?(?) ? ?(?), it commutes with ? and ?, and if detailed maps satisfy the following contractive condition.
?(??, ??, ??) ? ???{ ?(??, ??, ?), ?(??, ??, ?), ?(??, ??, ?)} for all ?, ? ? ?, ? ? (0, ?) and 0 < ? < 1 ? (3.11)
Additionally, lim ??? ?(?, ?, ?) = ? ?? , for all ?, ? ? ? and ? ? [0, Then ?, ?, and ? have a unique common fixed point.
Proof: ?? ? is a Cauchy sequence?
Since ? is a continuous mapping from ? to ?(?) ? ?(?) so for ? 1 ? ?, there exists any ? 0 ? ? such that ?? 0 = ?? 1 and ?? 0 = ?? 1
On keep repeating this process for different ? 1 and ? 0 , we get a sequence {? ? } such that In general, we get ?(?? ?+1 , ?? ?+2 , ??) ? ?(?? ? , ?? ?+1 , ?), ? ? > 0 ? (???)
??Hence by lemma (4.2), {?? ? } is a Cauchy sequence in ?.
Since the space ? is complete, so there exists some ? ? ? such that lim The mappings ? and ? are continuous. ? is continuous from ? to ?(?) ? ?(?).
Clearly, ?(?) ? ?(?) and ?(?) ? ?(?)
This implies that ?(?) ? ?(?) ? ?(?).
| Def.2.5. [25]. Complex Valued Continuous t-norm | |||||
| A binary operation * ? ? 2 ], is | |||||
| called complex valued continuous t-norm if it satisfies the following conditions: | |||||
| (1) * is associative and commutative, | |||||
| (2) * is continuous, | |||||
| (3) ? 2 | ]. | ||||
| (iii) ? * ? = { | min{?, ?} , ?ð??" max{?, ?} = ? ?? ; 0, ?????????, | for a fix ? ? [0, | ? 2 | ]. | |
? ? [0, 1]. Ex.2.5. [25]. The following binary operations defined in (i), (ii) and (iii) are complex valued continuous t-norm (i) ? * ? = ??? (?, ?). (ii) ? * ? = ??? (? + ? -? ?? , 0), for a fix ? ? [0, Def.2.6. [25]. Complex Valued Fuzzy Metric Spaces (CVFMS)
| Lemma 2.7 [25]. Let (?, ?, * ) be a CVFMS such that lim ??? | ?(?, ?, ?) = ? ?? , for all ?, ? ? | |
| ?, if ?(?, ?, ??) ? ?(?, ?, ?), for all ?, ? ? ?, 0 < ? < 1, ? ? (0, ?) then ? = ?. | ||
| Lemma 2.8 [25]. Let {? ? } be a sequence in a CVFMS (?, ?, * ) with lim ??? | ?(?, ?, ?) = ? ?? , | |
| for all ?, ? ? ?. If there exists a number ? which lies on (0, 1)such that | ||
| ?(? ?+1 , ? ?+2 , ??) ? ?(? ? , ? ?+1 , ?), ? ? > 0, ? = 0, 1, 2, . .. Then {? ? } is a Cauchy | ||
| sequence in ?. | ||
The following theorem was established bySingh et al. [25], which is the resetting of the Banach contraction principle in CVFMS. Theorem 2.7 [25]. Let (?, ?, * ) be a CVFMS such that lim ??? ?(?, ?, ?) = ? ?? , ? ?, ? ? ?,
Common fixed point theorems in complex valued metric spaces. Numerical Functional Analysis and Optimization 2011. Results on Complex Valued Complete Fuzzy Metric Spaces. 32 (3) p. .
On some results in fuzzy metric spaces. Fuzzy Sets System 64 p. .
Mapping with a common fixed point. Math. Sem. Notes Kobe Univ 1979. 7 p. .
Some remarks on fuzzy complex analysis. Fuzzy Sets System 1999. 106 p. .
Notes on a?AIJon the restudy of fuzzy ?complex analysis: Part I and part IIa?A? ?I. Fuzzy Sets System 2008. 159 p. .
Notes on fuzzy complex analysis. Fuzzy Sets System 2009. 160 p. .
A novel framework of complex-valued fuzzy metric spaces and fixed-point theorems. Journal of Intelligent and fuzzy system 2016. 30 p. .
Rouz ar an M. Im a , Some common ixe point t eorems on comp ex-va ue metric spaces. Computer and Mathematics with Applications 1012. 64 p. .
Fuzzy logic systems for engineering: A tutorial. Fuzzy Sets and Fuzzy Logic: Theory and Applications, (NJ
Commuting maps and fixed points. Amer Math Monthly 1976. 83 p. .
Fuzzy metric and statistical metric spaces. Kybernetica 1975. 11 p. .
Issue 2 | Compilation 1.0 Results on Complex Valued Complete Fuzzy Metric Spaces. London Journal of Research in Science: Natural and Formal 15 p. 63.
Fuzzy complex numbers. Proc ISFK, (ISFKGuangzhou, China
Fuzzy complex numbers. Fuzzy Sets System 1989. 33 p. .
Fuzzy complex analysis II: Integration. Fuzzy Sets System 1992. 49 p. .
On the restudy of fuzzy complex analysis: Part I. The sequence and series of fuzzy complex numbers and their convergences. Fuzzy Sets System 2000. 115 p. .
On the restudy of fuzzy complex analysis: Part II. The continuity and differentiation of fuzzy complex functions. Fuzzy Sets System 2001. 120 p. .
Fuzzy sets. Inform Control 1965. 8 p. .
Fixed points in fuzzy metric spaces. Fuzzy Sets and System 1988. 27 p. .
Semi-continuity of complex fuzzy function. Tsinghua Science and Technology 2003. 8 p. .
Probabilistic interpretation of complex fuzzy set. IJCSEIT 2012. 2 (2) p. .
Common fixed point theorems using property (E.A) in complex-valued metric spaces. Thai Journal of Mathematics 2013. 11 (2) p. .
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