1. Introduction
The Yang–Baxter equation, introduced independently by C.N. Yang in theoretical physics [
1] and by R.J. Baxter in statistical mechanics [
2,
3], has become a fundamental subject across diverse fields, including knot theory, quantum computing, braided categories, quantum groups, integrable systems, and quantum mechanics. It also plays a significant role in pure mathematics, particularly in the context of set-theoretical solutions within algebraic structures.
Numerous researchers have explored various algebraic structures influenced by the Yang–Baxter equation. For example, Berceanu et al. [
4] investigated algebraic systems arising from Yang–Baxter systems, while Oner and Senturk [
5] developed novel set-theoretical solutions within the framework of MV-algebras. Additionally, Şentürk et al. addressed set-theoretical solutions for the Yang–Baxter equation within the framework of triangle algebras [
6]. Belavin and Drinfeld [
7] examined solutions to the classical Yang–Baxter equation for simple Lie algebras, and Senturk and Bozdağ [
8] employed a geometric approach to analyze set-theoretical solutions in Lie algebras. Additionally, Massuyeau and Nichita [
9] tackled the problem of constructing knot invariants using Yang–Baxter operators associated with unitary associative algebra structures, while Gateva-Ivanova [
10] studied set-theoretical solutions of the Yang–Baxter equation in relation to braces and symmetric groups. Wang and Ma [
11] introduced a framework for obtaining singular solutions to the quantum Yang–Baxter equation by constructing weak quasi-triangular structures. Furthermore, Nichita and Parashar [
12] investigated spectral-parameter-dependent Yang–Baxter operators and Yang–Baxter systems derived from algebraic structures, illustrating the ongoing interest in the diverse applications of the Yang–Baxter equation.
The Yang–Baxter equation has also found applications in quantum computing, where it connects to universal quantum gates and plays a role in unifying non-associative algebraic structures. In recent work [
13], Nichita has proposed structures that unify associative, Lie, and Jordan algebras, further expanding the Yang–Baxter equation’s mathematical scope.
Building on these foundational studies, set-theoretical solutions to the Yang–Baxter equation have gained prominence as a versatile framework for exploring algebraic structures and their interactions. Etingof, Schedler, and Soloviev [
14] laid the groundwork for understanding such solutions by formalizing their role in the study of quantum groups and integrable systems. Lu, Yan, and Zhu [
15] extended this perspective by introducing novel classifications and methods to analyze these solutions. Rump [
16] revolutionized the field by connecting the Yang–Baxter equation with braces and radical rings, thereby providing a unifying algebraic approach. Subsequent work by Guarnieri and Vendramin [
17] further developed the theory of skew braces, offering new insights into non-commutative solutions of the Yang–Baxter equation and their potential applications in mathematical physics.
Recent advances have expanded the applicability of set-theoretical solutions, particularly in understanding their structural properties. Catino et al. [
18] and Catino, Colazzo, and Stefanelli [
19] introduced the concept of matched products, demonstrating how set-theoretical solutions can be combined to create more complex structures. Jespers and Vendramin [
20] examined the role of structure groups in analyzing these solutions, while Cedó and Okniński [
21] focused on constructing finite simple solutions. Moreover, Cedó et al. [
22] explored primitive solutions, emphasizing their foundational role in the study of algebraic invariants. Smoktunowicz [
23] contributed by refining the theoretical underpinnings of these solutions, addressing both classical and quantum versions of the equation. Together, these studies underscore the continuing evolution of set-theoretical solutions, bridging theoretical advancements and practical applications.
In non-classical logic, GE-algebras (generalized exchange algebras) have been introduced as a generalization of Hilbert algebras. Studies by Bandaru et al. [
24,
25] have examined transitive and commutative GE-algebras, showing how they can be transformed into implication algebras or dual implicative BCK-algebras under certain conditions.
In this manuscript, we provide set-theoretical solutions to the Yang–Baxter equation within the framework of GE-algebras. By constructing mappings that satisfy the braid condition, we explore how the algebraic properties of GE-algebras contribute to these solutions. Through detailed proofs and the introduction of left and right translation operators, we analyze the interactions within the algebra. Furthermore, we propose an algorithm that automates the verification of these solutions, enabling broader applications in fields such as quantum mechanics and mathematical physics.
The paper is organized as follows: In
Section 2, we recall relevant definitions and results for GE-algebras and the Yang–Baxter equation. In
Section 3, we demonstrate that specific mappings satisfy the braid condition, essential for solving the Yang–Baxter equation, and introduce left and right translation operators to analyze their algebraic interactions. In
Section 4, we apply the Yang–Baxter equation to spin transformations, using GE-algebras to model quantum mechanical spin-
systems. The transformations, represented by a Cayley table, are analyzed algebraically to verify their physical relevance. An algorithm is then presented to automate the verification of these transformations as solutions to the Yang–Baxter equation, offering new insights into the role of GE-algebras in quantum spin systems.
3. Set-Theoretical Solutions for Yang–Baxter Equation on GE-Algebras
During this section, we provide a set-theoretical solution to the Yang–Baxter equation in the context of GE-algebras. The primary goal is to demonstrate that various mappings satisfy the braid condition, a critical criterion for solving the Yang–Baxter equation. The solutions are derived based on specific properties of the GE-algebra structure, with detailed steps verifying the required conditions.
Initially, we establish Lemma 1, which introduces a series of mappings on the GE-algebra, illustrating how each can serve as a solution to the Yang–Baxter equation. The proof verifies that these mappings satisfy the necessary braid condition by leveraging the algebraic properties of the GE-algebra. Additionally, we introduce left and right translation operators and examine how these mappings interact under the algebra’s operation. We further extend the analysis to demonstrate the properties of these operators, showing their consistency with the braid condition.
Through examples and detailed proofs, we validate the set-theoretical solutions for specific cases, such as when the mappings involve constant elements or follow defined rotation and reflection operations. Finally, we provide an algorithm to automate the verification of these solutions, allowing for broader application and eliminating the need for manual computations. The overall aim is to show that the proposed solutions to the Yang–Baxter equation on GE-algebras hold across different configurations, contributing to the understanding of how these algebraic structures apply in mathematical physics.
Lemma 1. Let be a GE-algebra. The following mappings serve as set-theoretical solutions to the Yang–Baxter equation, where γ denotes a constant in such that :
- (i)
S is the identity map;
- (ii)
;
- (iii)
;
- (iv)
;
- (v)
;
- (vi)
;
- (vii)
.
Proof. Let
and
be defined as follows:
We now demonstrate the equation
for all
:
Thus, serves as a set-theoretical solution of the Yang–Baxter equation in GE-algebras. □
The proofs of the remaining parts of Lemma 1 follow a similar approach as the proof of part (v).
Definition 6. Let be a GE-algebra and . The mappings and are defined on G as follows:for each . Proposition 1. Let be a GE-algebra. Then, the mappings and satisfy the following properties:
- (i)
;
- (ii)
;
- (iii)
;
- (iv)
;
- (v)
;
for each .
Proof. (i)–(ii): By applying Theorem 1 (iv), we obtain and .
(iii)–(iv): It follows directly that for each by Theorem 1 (i), and similarly, by Definition 1 ().
(v): We have by the definitions of the mappings and by Definition 1 (). □
Lemma 2. The following results hold for any GE-algebra:
- (i)
, where ;
- (ii)
, where ;
for each and .
Proof. (i): To verify the identity using the method of induction, we begin by establishing the base case and then proceed with the inductive step:
Base case: For , the result is evident.
Inductive step: Assume the identity holds for . We aim to show its validity for .
Using Theorem 1
(ii), we derive the following equality:
Thus, by induction, the identity holds for all positive integers k.
Base case: For , the result is self-evident by Definition 1 .
Inductive step: Assume the identity holds for with . We aim to show it holds for .
By Theorem 1
, we derive the following equality:
Thus, by induction, the identity
holds for all positive integers
. □
Now, we provide the following algorithm, which can be executed using a computer system, eliminating the need for manual calculations to obtain Lemma 2.
Algorithm 1 aims to verify the two key conditions of Lemma 2 for a given GE-algebra . The algorithm systematically checks whether the mapping satisfies the identities for all , and for all , as stated in the lemma. The verification process is divided into two main steps:
Step 1: Verification of Condition (i)
In this step, the algorithm iterates through each element to verify that the identity holds for all positive integers . The algorithm first establishes the base case for and then proceeds to check larger values of k. For each value of k, the recursive definition of is computed as , ensuring consistency with the condition stated in Lemma 2. If any value of k fails to satisfy this condition, the algorithm immediately returns False.
Step 2: Verification of Condition (ii)
This step checks whether the identity holds for all . The algorithm starts by verifying the base case at . It then recursively computes for using the expression . If the computed result does not equal 1 for any k, the algorithm returns False.
If both steps are successfully verified for all relevant values of k, the algorithm concludes that Lemma 2 holds and returns True. This systematic approach ensures that the required conditions for the GE-algebra are thoroughly checked, thereby automating the verification process.
Lemma 3. The following results hold for any GE-algebra:
- (i)
, where ;
- (ii)
for each and .
Proof. The results can be demonstrated using a technique similar to the one used in the proof of Lemma 2. □
Algorithm 1: Verification of Lemma 2 for a GE-Algebra |
![Axioms 13 00846 i001]() |
Proposition 2. The following equalities hold for any GE-algebra:
- (i)
- (ii)
for each .
Proof. (i) Using Theorem 1
(ix) and
(iii), and substituting
and
, we obtain the following result:
for each
. The remaining equalities can be shown using a similar technique.
Lemma 4. Let be a GE-algebra. The mappings
- (i)
- (ii)
satisfy the braid condition on this structure, where . Consequently, they serve as set-theoretical solutions of the Yang–Baxter equation on .
Proof. (i) We demonstrate that the mapping satisfies the braid condition on this structure. Using Lemma 2
(i), we obtain the following equalities:
(ii) By a similar method as in
(i), we can demonstrate that the mapping
satisfies the braid condition. □
Proposition 3. Let be a GE-algebra. The mappings
- (i)
- (ii)
satisfy the braid condition on this structure, where and . Consequently, they serve as set-theoretical solutions of the Yang–Baxter equation on .
Proof. The results can be derived directly using Lemmas 2 and 4. □
Example 1. Consider the set . The binary operation ∗ on G is defined as shown in Table 1. Then, the structure forms a GE-algebra. Now, we demonstrate that the function satisfies the braid condition for all elements .and Since Equations (12) and (13) must be identical, the following equalities are derived: The validation of Equations (7) and (9) is facilitated by Lemma 2 (i). Demonstrating the verification of Equation (8) will establish the fulfillment of the braid condition for the provided function in this example. We then consider the following cases: After evaluating each case, we establish that holds true for every . Consequently, we demonstrate that satisfies the braid condition for all .
Example 2. Let be the GE-algebra given in Example 1. We demonstrate that the mappingdoes not satisfy the braid condition on this structure. With the aid of Example 1, it is evident that at least one of the identitiesis not satisfied in the braid condition on this structure, as illustrated by the following counterexample:for . Considering Examples 1 and 2, a natural question arises:
“Does the function satisfy the braid condition for any ?”
To address this question, we first introduce the following definition and lemma.
Definition 7. A GE-algebra is said to be strictly transitive if it satisfies the conditionfor all elements . Lemma 5. Let be a strictly transitive GE-algebra. Then, the identityholds for each . Proof. By applying Theorem 1
(ix) twice and using Definition 7, we derive the following:
for any
. □
Theorem 2. Let be a transitive GE-algebra. Then, the mapping satisfies the braid condition for any elements .
Proof. Assume that
is a transitive GE-algebra. Then, we have the following equalities:
and
As Equations (12) and (13) must be identical, the following equalities hold:
The verification of Equations (
14) and (16) is facilitated by Lemma 2
(i). Demonstrating the validity of Equation (15) establishes the fulfillment of the braid condition for the provided function in any GE-algebra. We examine the following cases:
Using Definition 1
(), we obtain the following identities from Equations (
17) and (18):
By Lemma 5, we conclude that
for any
. As a result, we conclude that the mapping
satisfies the braid condition for any elements
. □
Proposition 4. Let be a commutative GE-algebra. Then, the following identities hold:
- (i)
- (ii)
for each
Proof. The result follows directly from Definitions 3 and 6. □
Lemma 6. Let be a commutative GE-algebra. If the identity holds, then β must equal γ.
Proof. Assume that
for any
Utilizing Definition 1, Proposition 4, and the given hypothesis, we derive the following:
□
Lemma 7. Let be a GE-algebra. Suppose that the following equalities hold:for all . Then, the mappingsatisfies the braid condition. Proof. Let
and
be defined as follows:
We now demonstrate the equation
for all
:
On the other hand, we have
Using the given Equalities (
21)–(
24) in the lemma, we can see that these two expressions are equal. Therefore, the mapping
S satisfies the braid condition. □
To verify whether a given mapping satisfies Lemma 7, we provide the following algorithm, which can be executed using a computer system, eliminating the need for manual calculations.
The purpose of Algorithm 2 is to determine whether a given mapping S on a set G satisfies the braid condition specified in Lemma 7. This algorithm systematically checks if the mapping S adheres to the braid condition by iteratively verifying its behavior across all elements of G.
The algorithm takes as input a set G, a mapping , functions , and specific parameters and . The output of the algorithm is a Boolean value indicating whether the mapping S satisfies the braid condition for every triplet of elements .
The core process involves the following steps:
Triple iteration: For each combination of elements , , and in G, the algorithm computes several intermediate mappings to verify the braid condition.
First intermediate step : The algorithm computes the initial mapping , which involves applying functions and on the pair and using the functions and to obtain the mapped output along with .
Second intermediate step : This intermediate step further applies the mapping on the output of the previous step. The algorithm carefully computes nested applications of the functions , , , and to generate the updated result.
Comparison of results: The algorithm computes both the left-hand side and right-hand side results of the braid condition and compares them for equality. If at any point, the results differ, the algorithm terminates and returns False, indicating that the braid condition is not satisfied for the mapping S.
Final check: If all combinations of , , and satisfy the braid condition, the algorithm returns lTrue.
Algorithm 2: Verification of Braid Condition for Lemma 7 |
![Axioms 13 00846 i002]() |
This algorithm is designed to automate the verification of the braid condition, ensuring that the entire set G is exhaustively checked without requiring manual calculations.
Now, we give the following Theorem with the help of Lemma 7.
Theorem 3. Let be a GE-algebra, and let the mapping S be defined asIf the mapping S satisfies and for all , then S satisfies the braid condition on G. Proof. Assume that the mapping
is defined such that
and
for all
. Using Lemma 7 and our assumption, we derive
and
Since Equations (
25) and (
26) yield the same result, the equality in Equation (
21) of Lemma 7 is verified.
Since Equations (
27) and (
28) produce the same result, the equality in Equation (
22) of Lemma 7 is confirmed.
Since Equations (
29) and (
30) yield the same result, the equality in Equation (
24) of Lemma 7 is verified.
Therefore, based on Lemma 7, we conclude that the mapping
satisfies the braid condition under the conditions
and
for all
. □
Lemma 8. Let be a GE-algebra. Suppose the following equalities hold for all : Then, the mappingsatisfies the braid condition on G. Proof. The result follows directly by applying a similar method as used in the proof of Lemma 7. □
Theorem 4. Let be a GE-algebra, and define the mapping S asIf S satisfies and for all , then S satisfies the braid condition on G. Proof. Assume that the mapping
is defined such that
and
for all
. Using Lemma 8 and our assumptions, we proceed as follows.
First, we demonstrate the equality in Equation (
31) of Lemma 8:
Additionally, we verify that
Since Equations (
34) and (
35) yield the same result, the equality in Equation (
31) of Lemma 8 is verified.
Next, we demonstrate the equality in Equation (
32) of Lemma 8:
Additionally, we establish the equality in Equation (
33) of Lemma 8:
Since Equations (
36) and (
37) yield the same result, the equality in Equation (
32) of Lemma 8 is verified.
Finally, we confirm the equality in Equation (
33) of Lemma 8:
Since Equations (
38) and (
39) yield the same result, the equality in Equation (
33) of Lemma 8 is verified.
Therefore, based on Lemma 8, we conclude that the mapping
satisfies the braid condition under the conditions
and
for all
. □
By combining Theorems 3 and 4, we present Algorithm 3 to determine whether the mappings
and
satisfy their respective conditions, as proven in these theorems. This algorithm systematically checks the conditions derived in the proofs of both theorems, ensuring that the mappings adhere to the braid condition on
G. The verification is carried out in two parts, addressing the left and right mappings independently within the framework of a GE-algebra.
Algorithm 3: Verification of the Theorems 3 and 4 in a GE-Algebra |
![Axioms 13 00846 i003]() |
Algorithm 3 aims to verify whether the mappings and satisfy the braid condition in a given GE-algebra . The algorithm combines the conditions presented in Theorems 3 and 4, which establish two distinct mappings defined using left and right operations on the set G. The purpose of the algorithm is to ensure that both mappings adhere to their respective conditions for the braid condition.
The algorithm consists of the following steps:
Verification for left mapping
In this step, the algorithm defines the left mapping
as
The algorithm iterates over all elements and in G and checks whether the conditions and hold. If these conditions are satisfied for every pair, then satisfies the braid condition on G. If any condition fails, the algorithm terminates and returns False.
Verification for right mapping
In this step, the algorithm defines the right mapping
as
The algorithm checks whether the conditions and are satisfied for all elements and in G. If both conditions hold for every pair, then is verified to satisfy the braid condition on G. If any condition fails, the algorithm returns False.
The algorithm returns True if both the left and right mappings and successfully satisfy their respective braid conditions. This combined approach ensures that the braid condition is comprehensively verified for both left and right mappings in the context of the GE-algebra.
Example 3. Let be the GE-algebra defined in Example 1. We define the mapping S as follows:where . The functions Ψ
and Ω
are defined from to G as follows: and According to Theorem 3, to verify that the mapping S satisfies the braid condition, we need to show that Given that , we use the left translation operator , defined as for all . Therefore, and .
We now analyze each case using the Cayley table provided in Example 1.
- (i)
For ,
According to the Cayley table, multiplying any element by results in Therefore, holds for these cases.
- (ii)
For ,
Using the Cayley table, we can check that Consequently, holds in all these cases, and thus is satisfied.
- (iii)
For ,
According to the Cayley table, Therefore, for any , we find that Thus, is satisfied.
- (iv)
For ,
Consequently, holds for all , so is satisfied.
By using Theorem 3, we have verified that the mappingsatisfies the braid condition on G. Therefore, the mapping S is a valid solution to the problem, fulfilling the necessary conditions according to the Cayley table in Example 1. 4. Application of the Yang–Baxter Equation to Spin Transformations in a GE-Algebra Framework
This section investigates the application of the Yang–Baxter equation to spin transformations using a GE-algebra framework. In quantum mechanics, the spin- system, such as an electron’s spin, is a fundamental type of angular momentum. The spin of a particle can occupy different quantum states, typically spin-up (↑) or spin-down (↓) along a chosen axis, such as the z-axis. Transformations, including rotations and reflections, affect these spin states.
We model these transformations using the elements of the set , where each element corresponds to a distinct transformation applied to the spin system. The element 1 represents the identity transformation, while the other elements capture specific rotations and reflections of the spin state.
The Cayley table provided illustrates the algebraic relationships between these transformations, showing how they combine and interact within the GE-algebra structure. Each transformation has a physical interpretation: rotations alter the spin’s orientation, and reflections mirror its configuration. These operations are consistent with how spin states evolve in quantum mechanics.
An example is provided to demonstrate how mappings based on these transformations can be verified using the braid condition, validating their role as set-theoretical solutions to the Yang–Baxter equation. This approach connects the algebraic framework to the physical behavior of spin systems.
Now, we define a binary operation
by the rule
The corresponding Cayley table for this operation is provided in
Table 2.
This structure corresponds to a GE-algebra. Moreover, we present a new approximation for the spin transformations within this GE-algebra. We suppose that each element of G corresponds to a specific transformation into the spin system:
: This element could represent a “reset” or null transformation that always returns the system to a neutral state, behaving like a reset operator.
: This element could represent a 180° rotation around the x-axis. Physically, this operation flips the spin of the particle from spin-up (↑) to spin-down (↓), or vice versa. It represents a fundamental transformation in spin systems, which inverts the spin’s orientation.
: This transformation could represent a 90° rotation around the y-axis, rotating the spin into a superposition state. Instead of a binary up or down state, the spin is now in a mixed state, partly aligned with the up or down directions. In quantum mechanics, this represents the ability to prepare a spin state that is neither fully up nor fully down but a combination of both.
: This transformation could correspond to a 180° rotation around the z-axis, which alters the phase of the spin state. Rotating around the z-axis preserves the magnitude of the spin but introduces a phase shift, affecting the wavefunction without flipping the spin.
: This element could represent a reflection across the xy-plane, which mirrors the spin’s configuration, effectively reversing its direction in certain states. Such reflections could be used to manipulate the spin state while preserving symmetries.
: This transformation could correspond to a 360° rotation around the x-axis. Unlike classical mechanics, where a 360° rotation would leave a system unchanged, in quantum mechanics a spin- particle gains a phase shift of after such a rotation. This transformation captures that effect, introducing a sign change in the wavefunction.
: This transformation could represent a combination of a rotation and a reflection. For example, it could correspond to a 180° rotation around the y-axis followed by a reflection across the xy-plane, yielding a complex change in the spin’s orientation.
1: This could be the identity transformation, which leaves the spin state unchanged. It acts as the identity element in this GE-algebra structure, meaning any transformation composed with 1 will yield the same transformation.
The Cayley table illustrates the interactions of these spin transformations within this approximation framework. For example, applying transformation (a 180° rotation around the x-axis) followed by transformation (a 90° rotation around the y-axis) yields transformation (reflection across the xy-plane) according to the defined mapping. This example highlights how the operations algebraically combine to generate new transformations under the operation *.
In this algebraic structure, the identity transformation (1) serves as the neutral element, while the other elements interact according to the rules defined in the table. These interactions are consistent with the physical transformations of spin systems, where each operation modifies the orientation of the spin state.
Example 4. Let be the GE-algebra defined in Cayley Table 2. We define the mapping S as follows:where . The functions Ψ
and Ω
are defined from to G as follows: and According to Theorem 4, to verify that the mapping S satisfies the braid condition, we need to show that Given that , we use the right translation operator defined as for all . Therefore, and .
We now analyze each case using Cayley Table 2. For , According to the Cayley table, we calculate for : Multiplying the resulting elements by γ, we can verify that .
For , According to the Cayley table, we calculate for : Multiplying the resulting elements by γ, we verify that .
For , Using the Cayley table, we calculate for : Multiplying the resulting elements by β, we verify that .
For , Using the Cayley table, we calculate for : Multiplying the resulting elements by β, we verify that .
Thus, using Theorem 4, we have verified that the mappingsatisfies the braid condition on G. Therefore, the mapping S is a valid solution to the problem, fulfilling the necessary conditions according to Cayley Table 2.