Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 6s (2025) 241 https://internationalpubls.com A Study of Bipolar Fuzzy Prime Ideals of a Lattice 1Venkata Kalyani U, 2B.V.S.N. Hari Prasad, 3Eswarlal. T, 4Aiyared Iampan 1Assistant Professor, Department of Mathematics and Statistics, Vignan’s Foundation for Science, Technology and Research, Vadlamudi, Guntur-522213, India. Email: u.v.kalyani@gmail.com 2Professor, Department of Mathematics, Vasireddy Venkatadri Institute of Technology, Nambur -522508, India. Email: bvsnhariprasad@gmail.com 3Associate Professor, Department of Mathematics, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Guntur, AP, India. Email: eswarlal@kluniversity.in 4Department of Mathematics, School of Science, University of Phayao, Mae Ka, Mueang, Phayao 56000, Thailand. Email: aiyared.ia@up.ac.th Article History: Received: 15-10-2024 Revised: 02-12-2024 Accepted: 10-12-2024 Abstract: This study explores the investigation of Bipolar Fuzzy Prime Ideals (BFPI) in lattices. We provide a detailed exploration of their properties, characterizations, and associated homomorphisms. Introduction: Fuzzy set theory, introduced by Zadeh L.A., is grounded in the concept of membership functions where each element in a set is assigned a membership degree ranging between 0 and 1. Although this model effectively combines supporting and opposing evidence for element membership, it lacks explicit representation of the uncertainty or dual nature of these evidence. To address this limitation, Gau and Buehrer introduced the concept of vague sets, characterized by two functions: one for membership and another for non-membership, where their sum does not exceed one. Further contributions to fuzzy set theory came from Atanassov's intuitionistic fuzzy sets and Bustince and Burillo's work showing their mathematical equivalence to vague sets. The dual-function approach of vague sets has been applied extensively in decision- making, control systems, and fault diagnosis. Lattice theory has also benefited from these advancements, with Ajmal and Thomas pioneering fuzzy sublattice theory, and later works exploring intuitionistic fuzzy lattices and vague lattices. Bipolar fuzzy sets (BFS), introduced by Lee K.M., extended fuzzy sets by incorporating dual notions of positive and negative membership values within a range of [-1, 1]. This extension enables interpretations of bipolar information, making BFS a valuable tool in decision-making and information processing. Objectives: Introduction of Bipolar fuzzy prime ideals of a Lattice, study of their characterizations and associated homomorphisms. Keywords: Bipolar fuzzy ideal, Bipolar fuzzy prime ideal, Bipolar fuzzy homomorphism, Bipolar fuzzy magnified translation. 1. Introduction Fuzzy set theory, introduced by Zadeh L.A. [1], is grounded in the concept of membership functions where each element in a set is assigned a membership degree ranging between 0 and 1. Although this model effectively combines supporting and opposing evidence for element membership, it lacks mailto:bvsnhariprasad@gmail.com mailto:eswarlal@kluniversity.in Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 6s (2025) 242 https://internationalpubls.com explicit representation of the uncertainty or dual nature of these evidences. To address this limitation, Gau and Buehrer [2] introduced the concept of vague sets, characterized by two functions: one for membership and another for non-membership, where their sum does not exceed one. Further contributions to fuzzy set theory came from Atanassov's intuitionistic fuzzy sets [5]and Bustince and Burillo's [3]work showing their mathematical equivalence to vague sets. The dual- function approach of vague sets has been applied extensively in decision-making, control systems, and fault diagnosis. Lattice theory has also benefited from these advancements, with Ajmal and Thomas pioneering fuzzy sublattice theory, and later works exploring intuitionistic fuzzy lattices and vague lattices. Bipolar fuzzy sets (BFS), introduced by Lee K.M.[6], extended fuzzy sets by incorporating dual notions of positive and negative membership values within a range of [-1, 1]. This extension enables interpretations of bipolar information, making BFS a valuable tool in decision-making and information processing. In particular, Ajmal. N and Thomas.K.V [7] both explored theory of (FL)fuzzy sublattice and introduced the idea of fuzzy sets to lattice theory. After then, in 2011, Thomas.K.V and Nair L.S.[4] presented idea of intuitionistic fuzzy lattices (IFLs). In 2017, Milles S [13] investigated the characterization of IFIs and IFFs based on lattice operations. Rao.R.P [15] later researched rough vague lattices in 2019. Nageswara Rao.B., RamaKrishna N and Eswarlal.T [14] introduced vague lattices(VL) in 2020. The principal IFI and IFF on a lattice were the subject of Boudaoud.S, Zedam.L and Milles S [10] study in 2020. Milles.S.[11] as well as studied the lattice of (IFT)intuitionistic fuzzy topologies produced by intuitionistic fuzzy relations in 2020. On residual lattices, Zhang H and Qingguo.Li [12] researched the (IFF)intuitionistic fuzzy filter theory. Bipolar vague cosets [9], Homomorphism on bipolar vague normal groups [8] were studied by Venkata Kalyani U in 2020. Later, Bipolar fuzzy sublattices were introduced in 2023 by Venkata Kalyani U and studied bipolar fuzzy ideals of a lattice [16]. Venkata Kalyani U studied the bipolar magnified fuzzy translation of a lattice [17] in 2024. Now, in this paper we introduce the theory of bipolar fuzzy prime ideals(BFPI) and their characterization using level sets and homomorphism of BFPI of a lattice. 2. Preliminaries Definition 2.1[7]: β€œA poset (𝔏, ≀ ) is called a lattice if Sup{ 𝑝, π‘ž } (also denoted by 𝑝 ∨ π‘ž ) and Inf{𝑝, π‘ž} (also denoted by 𝑝 ∧ π‘ž) exists for every pair of elements 𝑝, π‘ž in 𝔏.” Definition 2.2[1]: β€œLet ϝ be any non-empty set. A mapping πœ“: ϝ β†’ [0,1] is called a fuzzy subset of ϝ.” Definition 2.3[1]: β€œLet πœ“: ϝ β†’ [0,1] be any FS. Then the set {πœ“(𝑝)/𝑝 ∈ ϝ} is called the image of πœ“ and is denoted by Im(πœ“). For 𝑑 ∈ [0,1], πœ“π‘‘ = {𝑝 ∈ ϝ/πœ“(𝑝) β‰₯ 𝑑} is called a level subset of πœ“.” Definition 2.4[2]: β€œA vague set πœ… in the universe of discourse ϝ is characterized by two 𝑀ship functions given by (i)A truth 𝑀ship function π‘‘πœ…: ϝ β†’ [0,1] and (ii) A false 𝑀ship function π‘“πœ…: ϝ β†’ [0,1], where π‘‘πœ…(𝑝) is a lower bound of the grade of 𝑀ship of 𝑝 derived from the evidence for 𝑝 and π‘“πœ…(𝑝) is a lower bound on the negation of 𝑝 derived from the evidence against 𝑝, with π‘‘πœ…(𝑝) + π‘“πœ…(𝑝) ≀ 1 ". Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 6s (2025) 243 https://internationalpubls.com We give below a formation of the definition of vague set in the following way, which makes Atanassov, K.T.s intuitionistic fuzzy sets and Gau, W.L. and Buehrer, D.J.[2] vague sets in a mathematically equivalent form. Definition 2.5[2]: β€œLet πœ… be a vague set of a universe ϝ with true 𝑀ship function π‘‘πœ… and false 𝑀ship function π‘“πœ…. For 𝛼, Ξ₯ ∈ [0,1] with 𝛼 ≀ Ξ₯, the (𝛼, Ξ₯ )- cut or vague cut of a vague set πœ… is the crisp subset of ϝ is given by πœ…(𝛼,Ξ₯) = {𝑝 ∈ ϝ/π‘‰πœ…(𝑝) β‰₯ [𝛼, Ξ₯]} i.e., πœ…(𝛼,Ξ₯) = {𝑝 ∈ ϝ/π‘‘πœ…(𝑝) β‰₯ 𝛼 and 1 βˆ’ π‘“πœ…(𝑝) β‰₯ Ξ₯}.” Definition 2.6[2]: β€œThe 𝛼-cut, πœ…π›Ό of the vague set πœ… is the ( 𝛼, 𝛼 )-cut of πœ… and hence given by πœ…π›Ό = {𝑝 ∈ ϝ/π‘‘πœ…(𝑝) β‰₯ 𝛼}.” Definition 2.7[6]: β€œSuppose ϝ be a universal set. A (𝐡𝐹𝑆) bipolar fuzzy set 𝔹 in ϝ is an object having the form 𝔹 = {< ℏ, 𝔹𝑃(ℏ), 𝔹𝑁(ℏ) >/ℏ ∈ ϝ} where 𝔹𝑃: ϝ β†’ [0,1] and 𝔹𝑁: ϝ β†’ [βˆ’1,0] are a positive and negative 𝑀ship functions, respectively.” Definition 2.8[6]: β€œ Let ϝ be a nonempty set, and let π”Ήπœ— , π”Ήπœ” ∈ 𝐡𝑃𝐹𝑆(ϝ). (i) π”Ήπœ— is a subset of π”Ήπœ”, denoted by π”Ήπœ— βŠ† π”Ήπœ”, if for each ℏ ∈ ϝ, π”Ήπœ— 𝑃(ℏ) ≀ π”Ήπœ” 𝑃 (ℏ) and π”Ήπœ— 𝑁(ℏ) β‰₯ π”Ήπœ” 𝑁 (ℏ). (ii) The complement of π”Ήπœ—, denoted by π”Ήπœ— 𝑐 = ((π”Ήπœ— 𝑐 )𝑁, (π”Ήπœ— 𝑐 )𝑃), is a 𝐡𝐹𝑆 in ϝ defined as: for each ℏ ∈ ϝ, π”Ήπœ— 𝑐 (ℏ) = (βˆ’1 βˆ’ π”Ήπœ— 𝑁(ℏ),1 βˆ’ π”Ήπœ— 𝑃(ℏ)), i.e., (π”Ήπœ— 𝑐 )𝑃(ℏ) = 1 βˆ’ π”Ήπœ— 𝑁(ℏ), (π”Ήπœ— 𝑐 )𝑁(ℏ) = βˆ’1 βˆ’ π”Ήπœ— 𝑁(ℏ). (iii) The intersection of π”Ήπœ— and π”Ήπœ”, denoted by π”Ήπœ— ∩ π”Ήπœ”, is a 𝐡𝐹𝑆 in ϝ defined as: for each ℏ ∈ ϝ, (π”Ήπœ— ∩ π”Ήπœ”)(ℏ) = (π”Ήπœ— 𝑁(ℏ) ∨ π”Ήπœ” 𝑁 (ℏ), π”Ήπœ— 𝑃(ℏ) ∧ π”Ήπœ” 𝑃 (ℏ)). (iv) The union of π”Ήπœ— and π”Ήπœ”, denoted by π”Ήπœ— βˆͺ π”Ήπœ”, is a 𝐡𝐹𝑆 in ϝ defined as: for each ℏ ∈ ϝ, (π”Ήπœ— βˆͺ π”Ήπœ”)(ℏ) = (π”Ήπœ— 𝑁(ℏ) ∧ π”Ήπœ” 𝑁 (ℏ), π”Ήπœ— 𝑃(ℏ) ∨ π”Ήπœ” 𝑃 (ℏ)). " Definition:2.9[17]: β€œLet 𝔅 =< 𝔅𝑃, 𝔅𝑁 > be a BFS in ϝ and (𝛼, πœ”) ∈ [0,1], (πœƒ, πœ—) ∈ [βˆ‡,0] Γ— [0,β–³]. By a BFMT of 𝐡 =< 𝔅𝑁 , 𝔅𝑃 >, we mean a BFS 𝑀 = {< π‘Ÿ, 𝔅(πœ”,πœ—) 𝑃 (π‘Ÿ), 𝔅(𝛼,πœƒ) 𝑁 (π‘Ÿ) >: π‘Ÿ ∈ ϝ} or simply as 𝑀 = {< π‘Ÿ, 𝔅𝑀 𝑃 (π‘Ÿ), 𝔅𝑀 𝑁 (π‘Ÿ) >: π‘Ÿ ∈ ϝ}, where 𝔅𝑀 𝑃 (π‘Ÿ) = 𝔅(πœ”,πœ—) 𝑃 : ϝ β†’ [0,1] and 𝔅𝑀 𝑁 = 𝔅(𝛼,πœƒ) 𝑁 : ϝ β†’ [βˆ’1,0] and defined by 𝔅𝑀 𝑃 (π‘Ÿ) = 𝔅(πœ”,πœ—) 𝑃 (π‘Ÿ) = πœ”π”…π‘ƒ(π‘Ÿ) + πœ— for all π‘Ÿ ∈ ϝ and 𝔅𝑀 𝑁 (π‘Ÿ) = 𝔅(𝛼,πœƒ) 𝑁 (π‘Ÿ) = 𝛼𝔅𝑁(π‘Ÿ) + πœƒ.” Definition:2.10[16]: β€œSuppose 𝔅 = (𝔅𝑃, 𝔅𝑁) is a BFS in 𝔏 where 𝔅𝑃: ϝ β†’ [0,1] and 𝔅𝑁: ϝ β†’ [βˆ’1,0]Then 𝔅 is known to be a BFL(Bipolar fuzzy sublattice) of 𝔏 when the following conditions are fulfilled for all ℏ, π‘š ∈ 𝔏, (𝑖)𝔅𝑃(β„β‹π‘š) β‰₯ min{𝔅𝑃(ℏ), 𝔅𝑃(π‘š)}, (ii) 𝔅𝑃(ℏ ∧ π‘š) β‰₯ min{𝔅𝑃(ℏ), 𝔅𝑃(π‘š)}. (iii) 𝔅𝑁(β„β‹π‘š) ≀ max{𝔅𝑁(ℏ), 𝔅𝑁(π‘š)}, (iv) 𝔅𝑁(ℏ ∧ π‘š) ≀ max{𝔅𝑁(ℏ), 𝔅𝑁(π‘š)}.” Definition:2.11[16]: β€œSuppose 𝔅 = (𝔅𝑃, 𝔅𝑁) is a BFS in 𝔏 where 𝔅𝑃: ϝ β†’ [0,1] and 𝔅𝑁: ϝ β†’ [βˆ’1,0]Then 𝔅 is known to be a BFIL(Bipolar fuzzy ideal) of 𝔏 when the following conditions are fulfilled for all ℏ, π‘š ∈ 𝔏, Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 6s (2025) 244 https://internationalpubls.com (𝑖)𝔅𝑃(β„β‹π‘š) β‰₯ min{𝔅𝑃(ℏ), 𝔅𝑃(π‘š)}, (ii) 𝔅𝑃(ℏ ∧ π‘š) β‰₯ max{𝔅𝑃(ℏ), 𝔅𝑃(π‘š)}. (iii) 𝔅𝑁(β„β‹π‘š) ≀ max{𝔅𝑁(ℏ), 𝔅𝑁(π‘š)}, (iv) 𝔅𝑁(ℏ ∧ π‘š) ≀ min{𝔅𝑁(ℏ), 𝔅𝑁(π‘š)}.” 3. Bipolar Fuzzy Prime Ideals of a Lattice In this section, we explore and study Bipolar Fuzzy prime ideals (BFPI) of 𝔏, their characterizations by using level subsets, homomorphism and anti-homomorphism of BFPIs. Now, we introduce the following. Definition 3.1: Suppose 𝔅 = (𝔅𝑃, 𝔅𝑁) is a BFI in 𝔏. Then 𝔅 is known to be a BFPI of 𝔏 when the following conditions are fulfilled for all ℏ, π‘š ∈ 𝔏, (i) 𝔅𝑃(ℏ ∧ π‘š) ≀ max{𝔅𝑃(ℏ), 𝔅𝑃(π‘š)}, (ii) 𝔅𝑁(ℏ ∧ π‘š) β‰₯ min{𝔅𝑁(ℏ), 𝔅𝑁(π‘š)}. Example 3.2: Consider the lattice 𝔏 of" divisors of 6 ". We get 𝔏 = {1,2,3,6}. Suppose 𝔅 = {< 1,0.7, βˆ’0.3 >, < 2,0.4, βˆ’0.3 >, < 3,0.7, βˆ’0.1 >, < 6,0.4, βˆ’0.1 >}. We can easily prove that 𝔅 is a BFPI of 𝔏. Theorem 3.3: Suppose 𝔅 = (𝔅𝑃, 𝔅𝑁) be a BFS(𝔏). Then it holds that 𝔅 is a BFPI on 𝔏 iff the following four statements hold: (i) 𝔅𝑃(ℏ ∨ π‘š) = min{𝔅𝑃(ℏ), 𝔅𝑃(π‘š)}, (ii) 𝔅𝑃(ℏ ∧ π‘š) = max{𝔅𝑃(ℏ), 𝔅𝑃(π‘š)}, (iii) 𝔅𝑁(ℏ ∨ π‘š) = max{𝔅𝑁(ℏ), 𝔅𝑁(π‘š)}, (iv) 𝔅𝑁(ℏ ∧ π‘š) = min{𝔅𝑁(ℏ), 𝔅𝑁(π‘š)} for any ℏ, π‘š ∈ 𝔏. Proof: Proof is clear. Theorem 3.4: If πœ… and 𝔅 are two BFPIs of a lattice 𝔏, then πœ… ∩ 𝔅 is a BFPI of 𝔏. Proof: Suppose πœ… = (πœ…π‘ƒ, πœ…π‘) and 𝔅 = (𝔅𝑃, 𝔅𝑁) be two BFPIs of 𝔏. Now, (πœ… ∩ 𝔅)𝑃(ℏ ∧ π‘š) = min{πœ…π‘ƒ(ℏ ∧ π‘š), 𝔅𝑃(ℏ ∧ π‘š)} ≀ min{max{πœ…π‘ƒ(ℏ), πœ…π‘ƒ(π‘š)}, max{𝔅𝑃(ℏ), 𝔅𝑃(π‘š)} = max{min{πœ…π‘ƒ(ℏ), 𝔅𝑃(ℏ)}, min{πœ…π‘ƒ(π‘š), 𝔅𝑃(π‘š)} = max{(πœ… ∩ 𝔅)𝑃(ℏ), (πœ… ∩ 𝔅)𝑃(π‘š)}. Thus (πœ… ∩ 𝔅)𝑃(ℏ ∧ π‘š) ≀ max{πœ… ∩ 𝔅)𝑃(ℏ), πœ… ∩ 𝔅)𝑃(π‘š)} for all ℏ, π‘š ∈ 𝔏. Now, (πœ… ∩ 𝔅)𝑁(ℏ ∧ π‘š) = max{πœ…π‘(ℏ ∧ π‘š), 𝔅𝑁(ℏ ∧ π‘š)} β‰₯ max{min{πœ…π‘(ℏ), πœ…π‘(π‘š)}, min{𝔅𝑁(ℏ), 𝔅𝑁(π‘š)} = min{max{πœ…π‘(ℏ), 𝔅𝑁(ℏ)}, max{πœ…π‘(π‘š), 𝔅𝑁(π‘š)} = min{(πœ… ∩ 𝔅)𝑁(ℏ), (πœ… ∩ 𝔅)𝑁(π‘š)}. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 6s (2025) 245 https://internationalpubls.com Thus (πœ… ∩ 𝔅)𝑁(ℏ ∧ π‘š) β‰₯ min{πœ… ∩ 𝔅)𝑁(ℏ), πœ… ∩ 𝔅)𝑁(π‘š)} for all ℏ, π‘š ∈ 𝔏 Hence, πœ… ∩ 𝔅 is a BFPI of 𝔏. Remark 3.5: Union of two BFPIs of a lattice 𝔏 need not be a BFPI. Since from [ ] union of two BFIs neednot be a BFI, hence, πœ… βˆͺ 𝔅 need not be a BFPI of 𝔏. Theorem 3.6: The arbitrary intersection of BFPIs of a complete lattice satisfying infinite meet distributive law 𝔏 is also a BFPI of 𝔏. Proof: Proof is clear. Theorem 3.7: Let B =< BP, BN >∈ BFS(𝔏). Then B is BFPI of 𝔏 if and only if the nonempty level subset B (Ξ±, Ο‰) is a prime ideal of 𝔏 for each Ξ± ∈ [0, 1] and Ο‰ ∈ [βˆ’1, 0]. Proof: Suppose that B =< BP, BN > is BFPI(𝔏). Let ℏ, m ∈ B (Ξ±, Ο‰). β‡’ BP (ℏ) β‰₯ Ξ±, BP (m) β‰₯ Ξ± and BN (ℏ) ≀ Ο‰, BN (m) ≀ Ο‰. To show that B (Ξ±, Ο‰) is a prime ideal of 𝔏, we show that for each ℏ, m ∈ 𝔏 and ℏ ∧ m ∈ B (Ξ±, Ο‰) then either ℏ ∈ B (Ξ±, Ο‰) or s ∈ B (Ξ±, Ο‰). Suppose ℏ, m ∈ 𝔏 and ℏ ∧ s ∈ B (Ξ±, Ο‰). Then BP (ℏ ∧ m) β‰₯ Ξ±, BN (ℏ ∧ m) ≀ Ο‰ β‡’ max {BP (ℏ), BP (m)} β‰₯ Ξ±, min {BP (ℏ), BP (m)} ≀ Ο‰ (since B is a BFPI of 𝔏) β‡’ BP (ℏ) β‰₯ Ξ± or BP (m) β‰₯ Ξ±, BN (ℏ) ≀ Ο‰ or BN (m) ≀ Ο‰ β‡’ BP (ℏ) β‰₯ Ξ± and BN (ℏ) ≀ Ο‰ or BP (m) β‰₯ Ξ± and BN (m) ≀ Ο‰ Thus ℏ ∈ B (Ξ±, Ο‰) or s ∈ B (Ξ±, Ο‰) Hence, B (Ξ±, Ο‰) is a prime ideal of 𝔏. In converse assume that B (Ξ±, Ο‰) is a prime ideal of 𝔏. i.e To any ℏ, m ∈ 𝔏 and ℏ ∧ s ∈ B (Ξ±, Ο‰) then either ℏ ∈ B (Ξ±, Ο‰) or s ∈ B (Ξ±, Ο‰). We have to show that B is a BFPI of 𝔏. Assume that B is not a BFPI of 𝔏. Thus BP (ℏ ∧ m) > max {BP (ℏ), BP (m)} and Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 6s (2025) 246 https://internationalpubls.com BN (ℏ ∧ m) < min {BN (ℏ), BN (m)} β‡’ BP (ℏ ∧ m) > BP (ℏ) and BP (ℏ ∧ m) > BP (m), BN (ℏ ∧ m) < BN (ℏ) and BN (ℏ ∧ m) < BN (m). Suppose that BP (ℏ ∧ m) = Ξ± and BN (ℏ ∧ m) = Ο‰ β‡’ BP (ℏ) < Ξ± and BN (ℏ) > Ο‰, BP (m) < Ξ± and BN (m) > Ο‰. Hence ℏ, m ∈/ B (Ξ±, Ο‰). This is a contradiction to the fact that B (Ξ±, Ο‰) is a prime ideal of 𝔏 for any Ξ± ∈ [0, 1] and Ο‰ ∈ [βˆ’1, 0]. Hence B is a BFPI of 𝔏. Theorem 3.8: Let 𝔏 be a lattice and B ∈ BFS (𝔏). If B, BFPI of 𝔏 then we have Supp(B) forms a crisp prime ideal of 𝔏. Proof: Suppose B = {< ℏ, BP (ℏ), BN (ℏ) > /ℏ ∈ 𝔏 } ∈ BFS (𝔏). Given B is a BFPI of 𝔏. From [] we have Supp(B) is a crisp ideal in 𝔏. Now we prove that Supp(B) is prime. Suppose ℏ, m ∈ 𝔏 so that ℏ ∧ s ∈ Supp(B). Thus BP (ℏ ∧ m) ΜΈ= 0 or BN (ℏ ∧ m) ΜΈ= 0. But BP (ℏ ∧ m) = max {BP (ℏ), BP (m)} (since B is BFPI of 𝔏). β‡’ either BP (ℏ) β‰ 0, or BP (m) β‰  0 Likewise, we have either BN (ℏ) β‰  0, or BN (m) β‰  0 β‡’ either ℏ ∈ Supp(B) or m ∈ Supp(B). Hence Supp(B) is a prime ideal of 𝔏. Remark 3.9: Converse part of the above theorem does not hold in general. Suppose B = {< 1, 0.5, βˆ’0.1 >, < 2, 0.7, βˆ’0.2 >, < 3, 0.8, βˆ’0.05 >, < 6, 0.4, βˆ’0.01 >} be a BF subset in 𝔏 = {1, 2, 3, 6} with divisors of 6. Supp(B) = {1, 2, 3, 6} is a prime ideal of 𝔏. But BP (2 ∧ 3) = BP (1) = 0.5 β‰₯ max{BP (2), BP (8)} = 0.8 β‡’ B is not a BFPI of 𝔏. Theorem 3.10: Let B be a BFS of lattice 𝔏. Then, B is a BFPI of 𝔏 if and only if f the BFMT M of B form BF prime ideal of 𝔏. Proof: Assume that 𝔅 is a BF primeideal of 𝔏 and 𝑀 be a BFMT of 𝔅. Now we have to show that 𝑀 is a BFPI of 𝔏. Let ℏ, π‘š ∈ 𝔏. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 6s (2025) 247 https://internationalpubls.com Now, consider 𝔅(πœ”,πœ—) 𝑃 (ℏ ∧ π‘š) = πœ”π”…π‘ƒ(ℏ ∧ π‘š) + πœ—. ≀ πœ” max{𝔅𝑃(ℏ), 𝔅𝑃(π‘š)} + πœ— 。 = max{πœ”π”…π‘ƒ(ℏ) + πœ—, πœ”π”…π‘ƒ(π‘š) + πœ—} = max{𝔅(πœ”,πœ—) 𝑃 (ℏ), 𝔅(πœ”,πœ—) 𝑃 (π‘š)} Thus 𝔅(πœ”,πœ—) 𝑃 (ℏ ∧ π‘š) ≀ max{𝔅(πœ”,πœ—) 𝑃 (ℏ), 𝔅(πœ”,πœ—) 𝑃 (π‘š)} Now 𝔅(𝛼,πœƒ) 𝑁 (ℏ ∧ π‘š) = 𝛼𝔅𝑁(ℏ ∧ π‘š) + πœƒ. β‰₯ 𝛼min{𝔅𝑁(ℏ), 𝔅𝑁(π‘š)} + πœƒ. = min{𝛼𝔅𝑁(ℏ) + πœƒ, 𝛼𝔅𝑁(π‘š) + πœƒ} = min{𝔅(𝛼,πœƒ) 𝑁 (ℏ), 𝔅(𝛼,πœƒ) 𝑁 (π‘š)} Thus 𝔅(𝛼,πœƒ) 𝑁 (ℏ ∧ π‘š) β‰₯ min{𝔅(𝛼,πœƒ) 𝑁 (ℏ), 𝔅(𝛼,πœƒ) 𝑁 (π‘š)} Hence the BFMT 𝑀 of 𝔅 is again a BFPI of 𝔏. In converse assume that 𝑀 a BFPI of 𝔏. Now, consider 𝔅𝑃(ℏ ∧ π‘š) = 1 πœ” (𝔅(πœ”,πœ—) 𝑃 (ℏ ∧ π‘š) βˆ’ πœ—) ≀ 1 πœ” (max{𝔅(πœ”,πœ—) 𝑃 (ℏ), 𝔅(πœ”,πœ—) 𝑃 (π‘š)} βˆ’ πœ—) = max { 1 πœ” (𝔅(πœ”,πœ—) 𝑃 (ℏ) βˆ’ πœ—), 1 πœ” (𝔅(πœ”,πœ—) 𝑃 (π‘š) βˆ’ πœ—)} = max{𝔅𝑃(ℏ), 𝔅𝑃(π‘š)}. Thus 𝔅𝑃(ℏ ∧ π‘š) ≀ max{𝔅𝑃(ℏ), 𝔅𝑃(π‘š)}. Likewise, we can prove 𝔅𝑁(ℏ ∧ π‘š) β‰₯ min{𝔅𝑁(ℏ), 𝔅𝑁(π‘š)}. Thus 𝑀 is a BF prime ideal of 𝐿. Hence the proof. Theorem 3.11: Let πœ›: 𝔏 β†’ 𝔏1 be a lattice epimorphism. If 𝔅 is a BFPI of 𝔏, then πœ›(𝔅) is a BFPI of 𝔏1 . Proof: Assume 𝔅 = (𝔅𝑃, 𝔅𝑁) a BFPI of 𝔏. Then by known Th we know that πœ›(𝔅) is a BFI in 𝔏1. Now we show that πœ›(𝔅) is prime. Let 𝑠, 𝑧 ∈ 𝔏1. Then Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 6s (2025) 248 https://internationalpubls.com πœ›(𝔅𝑃)(𝑠 ∧ 𝑧) = sup{𝔅𝑃(ℏ) ∣ ℏ ∈ πœ›βˆ’1(𝑠 ∧ 𝑧)} = sup{𝔅𝑃(𝑒 ∧ πœ‰) ∣ 𝑒 ∈ πœ›βˆ’1(π‘š), πœ‰ ∈ πœ›βˆ’1(𝑧)} = sup{max{𝔅𝑃(𝑒), 𝔅𝑃(πœ‰)} ∣ 𝑒 ∈ πœ›βˆ’1(π‘š), πœ‰ ∈ πœ›βˆ’1(𝑧)} = max {sup{𝔅𝑃(𝑒) ∣ 𝑒 ∈ πœ›βˆ’1(π‘š)}, sup{𝔅𝑃(πœ‰) ∣ πœ‰ ∈ πœ›βˆ’1(𝑧)}} = max{πœ›(𝔅𝑃)(π‘š), πœ›(𝔅𝑃)(𝑧)}. πœ›(𝔅𝑁)(𝑠 ∧ 𝑧) = inf{𝔅𝑁(ℏ) ∣ ℏ ∈ πœ›βˆ’1(𝑠 ∧ 𝑧)} = inf{𝔅𝑁(𝑒 ∧ πœ‰) ∣ 𝑒 ∈ πœ›βˆ’1(π‘š), πœ‰ ∈ πœ›βˆ’1(𝑧)} = inf{min{𝔅𝑁(𝑒), 𝔅𝑁(πœ‰)} ∣ 𝑒 ∈ πœ›βˆ’1(π‘š), πœ‰ ∈ πœ›βˆ’1(𝑧)} = min {inf{𝔅𝑁(𝑒) ∣ 𝑒 ∈ πœ›βˆ’1(π‘š)}, inf{𝔅𝑁(πœ‰) ∣ πœ‰ ∈ πœ›βˆ’1(𝑧)}} = min{πœ›(𝔅𝑁)(π‘š), πœ›(𝔅𝑁)(𝑧)}, Hence, πœ›(𝔅) is a BFPI of 𝔏1. Theorem 3.12: Let πœ›: 𝔏 β†’ 𝔏1 be a lattice homomorphism. If 𝐢 is a BFPI of 𝔏1, then πœ›βˆ’1(𝐢) is a BFPI of 𝔏. Proof: Suppose 𝐢 = (𝐢𝑃, 𝐢𝑁) be a BFPI of 𝔏1. Then by known theorem[], we know that πœ›βˆ’1(𝐢) is a BFI in 𝔏. Now we show that πœ›βˆ’1(𝐢) is prime. Let ℏ, π‘š ∈ 𝔏. Then πœ›βˆ’1(𝐢𝑃)(ℏ ∧ π‘š) = 𝐢𝑃(πœ›(ℏ ∧ π‘š)) = 𝐢𝑃{(πœ›(ℏ) ∧ πœ›(π‘š)} = max{𝐢𝑃(πœ›(ℏ)), 𝐢𝑃(πœ›(π‘š))} = max{πœ›βˆ’1(𝐢𝑃)(ℏ), πœ›βˆ’1(𝐢𝑃)(π‘š)} πœ›βˆ’1(𝐢𝑁)(ℏ ∧ π‘š) = 𝐢𝑁(πœ›(ℏ ∧ π‘š)) = 𝐢𝑁{(πœ›(ℏ) ∧ πœ›(π‘š)} = min{𝐢𝑁(πœ›(ℏ)), 𝐢𝑁(πœ›(π‘š))} = min{πœ›βˆ’1(𝐢𝑁)(ℏ), πœ›βˆ’1(𝐢𝑁)(π‘š)} Hence, πœ›βˆ’1(𝐢) is a BFPI of 𝔏. 4.Conclusion This study explores the investigation of Bipolar Fuzzy Prime Ideals (BFPI) in lattices. We provide a detailed exploration of their properties, characterizations, and associated homomorphisms. References: [1] Gau, W.L., Buehrer, D.J.: Vague sets. IEEE Transactions on Systems, Man, and Cybernetics 23 (1993) 610–614. [2] L.A. Zadeh, Fuzzy Sets, Inform. Control. 8 (1965), 338-353. https://doi.org/10.1016/s0019-9958(65) 90241-x. [3] Bustince, H., Burillo, P.: Vague sets are intuitionistic fuzzy sets. Fuzzy Sets and Systems 79 (1996) 403–405 [4] K.V. Thomas, L.S. 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