EUROPEAN JOURNAL OF PURE AND APPLIED MATHEMATICS Vol. 11, No. 3, 2018, 876-881 ISSN 1307-5543 – www.ejpam.com Published by New York Business Global Introducing Partial Transformation UP-Algebras∗ Aiyared Iampan1,∗, Phakawat Mosrijai1, Akarachai Satirad1 1 Department of Mathematics, School of Science, University of Phayao, Phayao 56000, Thailand Abstract. The main aim of this paper is to introduce the notion of a partial transformation UP- algebra P (X) induced by a UP-algebra X and prove that the set of all full transformations T (X) is a UP-ideal of P (X). 2010 Mathematics Subject Classifications: 03G25 Key Words and Phrases: UP-algebra, partial transformation, full transformation. 1. Introduction and Preliminaries Iampan [2] introduced a new algebraic structure, called a UP-algebra, which is a gener- alization of a KU-algebra. Many researchers have studied on UP-algebras such as [4, 6, 7]. Let X be a universal set and let Ω ∈ P(X). Denote PΩ(X) = {A ∈ P(X) | Ω ⊆ A} and PΩ(X) = {A ∈ P(X) | A ⊆ Ω}. Define a binary operation · on PΩ(X) by putting A ·B = B ∩ (A′ ∪ Ω) for all A,B ∈ PΩ(X) and a binary operation ∗ on PΩ(X) by putting A ∗B = B ∪ (A′ ∩ Ω) for all A,B ∈ PΩ(X). Satirad et al. [5] proved that (PΩ(X), ·,Ω) and (PΩ(X), ∗,Ω) are UP-algebras. In partic- ular, (P(X), ·, ∅) and (P(X), ∗, X) are UP-algebras. In this paper, we introduce the notion of a partial transformation UP-algebra P (X) induced by a UP-algebra X and prove that the set of all full transformations T (X) is a UP-ideal of P (X). Now we will recall the definition of a UP-algebra from [2]. An algebra X = (X, ·, 0) of type (2, 0) is called a UP-algebra where X is a nonempty set, · is a binary operation on X, and 0 is a fixed element of X (i.e., a nullary operation) if it satisfies the following axioms: for any x, y, z ∈ X, ∗This work was financially supported by the University of Phayao. ∗Corresponding author. DOI: https://doi.org/10.29020/nybg.ejpam.v11i3.3296 Email addresses: aiyared.ia@up.ac.th (A. Iampan), phakawat.mo@gmail.com (P. Mosrijai), akarachai.sa@gmail.com (A. Satirad) http://www.ejpam.com 876 c© 2018 EJPAM All rights reserved. A. Iampan, P. Mosrijai, A. Satirad / Eur. J. Pure Appl. Math, 11 (3) (2018), 876-881 877 (UP-1) (y · z) · ((x · y) · (x · z)) = 0, (UP-2) 0 · x = x, (UP-3) x · 0 = 0, and (UP-4) x · y = 0 and y · x = 0 imply x = y. In a UP-algebra X = (X, ·, 0), the following assertions are valid (see [2, 3]). (∀x ∈ X)(x · x = 0), (1.1) (∀x, y, z ∈ X)(x · y = 0, y · z = 0⇒ x · z = 0), (1.2) (∀x, y, z ∈ X)(x · y = 0⇒ (z · x) · (z · y) = 0), (1.3) (∀x, y, z ∈ X)(x · y = 0⇒ (y · z) · (x · z) = 0), (1.4) (∀x, y ∈ X)(x · (y · x) = 0), (1.5) (∀x, y ∈ X)((y · x) · x = 0⇔ x = y · x), (1.6) (∀x, y ∈ X)(x · (y · y) = 0), (1.7) (∀a, x, y, z ∈ X)((x · (y · z)) · (x · ((a · y) · (a · z))) = 0), (1.8) (∀a, x, y, z ∈ X)((((a · x) · (a · y)) · z) · ((x · y) · z) = 0), (1.9) (∀x, y, z ∈ X)(((x · y) · z) · (y · z) = 0), (1.10) (∀x, y, z ∈ X)(x · y = 0⇒ x · (z · y) = 0), (1.11) (∀x, y, z ∈ X)(((x · y) · z) · (x · (y · z)) = 0), and (1.12) (∀a, x, y, z ∈ X)(((x · y) · z) · (y · (a · z)) = 0). (1.13) From now on, X will always denote a UP-algebra (X, ·, 0). Definition 1. [2] A subset S of X is called a UP-subalgebra of X if the constant 0 of X is in S, and (S, ·, 0) itself forms a UP-algebra. Iampan [2] proved the useful criteria that a nonempty subset S of a UP-algebra X is a UP-subalgebra of X if and only if S is closed under the · multiplication on X. Definition 2. [2, 8] A subset S of X is called (1) a UP-filter of X if it satisfies the following properties: (i) the constant 0 of X is in S, and (ii) for any x, y ∈ X,x · y ∈ S and x ∈ S imply y ∈ S. (2) a UP-ideal of X if it satisfies the following properties: (i) the constant 0 of X is in S, and (ii) for any x, y, z ∈ X,x · (y · z) ∈ S and y ∈ S imply x · z ∈ S. (3) a strongly UP-ideal of X if it satisfies the following properties: A. Iampan, P. Mosrijai, A. Satirad / Eur. J. Pure Appl. Math, 11 (3) (2018), 876-881 878 (i) the constant 0 of X is in S, and (ii) for any x, y, z ∈ X, (z · y) · (z · x) ∈ S and y ∈ S imply x ∈ S. Guntasow et al. [1] proved the generalization that the notion of UP-subalgebras is a generalization of UP-filters, the notion of UP-filters is a generalization of UP-ideals, and the notion of UP-ideals is a generalization of strongly UP-ideals. Moreover, they also proved that a UP-algebra X is the only one strongly UP-ideal of itself. 2. Main Results We denote B(X) the set of all binary relations on X, P (X) the set of all partial transformations on X, T (X) the set of all full transformations on X. Then T (X) ⊆ P (X) ⊆ B(X). If α ∈ B(X) and x ∈ X, then xα = {y ∈ X | (x, y) ∈ α}. Thus xα is the set of all elements that are α-related to x. Define a function O from X to X by O(x) = 0 for all x ∈ X, that is, O ∈ T (X). Define a binary operation • on B(X) by: for all α, β ∈ B(X), (x, y) ∈ α • β ⇔ { x ∈ domα ∩ domβ and y = yxα · yxβ for yxα ∈ xα and yxβ ∈ xβ, or x /∈ domα and y = 0. We can redefine a binary operation • on P (X) by: for all α, β ∈ P (X), (α • β)(x) = { α(x) · β(x) if x ∈ domα ∩ domβ, 0 if x /∈ domα. We see that • for all α, β ∈ B(X), dom (α • β) = (domα− domβ) ′ , (2.1) • the empty function ∅ ∈ P (X) and for all α ∈ P (X), ∅ • α = O and α • ∅ = O|(domα)′ . (2.2) Theorem 1. B(X) = (B(X), •, O) is an algebra of type (2, 0) satisfying (UP-2) and (UP-3). Proof. Let α ∈ B(X). Then (x, y) ∈ O • α⇔ x ∈ X ∩ domα and y = rxO · yxα for some yxα ∈ xα (domO = X) ⇔ x ∈ domα and y = O(x) · yxα for some yxα ∈ xα A. Iampan, P. Mosrijai, A. Satirad / Eur. J. Pure Appl. Math, 11 (3) (2018), 876-881 879 ⇔ x ∈ domα and y = 0 · yxα for some yxα ∈ xα ⇔ x ∈ domα and y = yxα for some yxα ∈ xα ((UP-2)) ⇔ (x, y) ∈ α. Hence, O • α = α, so (UP-2) is holding. Let α ∈ B(X) and x ∈ X. Then Case 1: x /∈ domα. Then (x, 0) ∈ (α •O)⇔ (x, 0) ∈ O. Case 2: x ∈ domα. Then (x, y) ∈ α •O ⇔ x ∈ domα ∩X and y = rxα · yxO for some yxO ∈ xO (domO = X) ⇔ x ∈ domα and y = rxα ·O(x) ⇔ x ∈ domα and y = rxα · 0 ⇔ x ∈ domα and y = 0 ((UP-3)) ⇔ (x, y) ∈ O. Hence, α •O = O, so (UP-3) is holding. Therefore, B(X) = (B(X), •, O) is an algebra of type (2,0) satisfying (UP-2) and (UP-3). Theorem 2. P (X) = (P (X), •, O) is a UP-algebra and we shall call it the partial trans- formation UP-algebra induced by a UP-algebra X. Proof. Let α, β, γ ∈ P (X) and let x ∈ X. Case 1: x /∈ domα. Then (α•β)(x) = 0 = (α•γ)(x), so x ∈ dom (α•β)∩dom (α•γ). Thus ((α • β) • (α • γ))(x) = (α • β)(x) · (α • γ)(x) = 0 · 0 = 0, ((UP-2)) so x ∈ dom ((α • β) • (α • γ)). Case 1.1: x /∈ dom (β • γ). Then ((β • γ) • ((α • β) • (α • γ)))(x) = 0 = O(x). Case 1.2: x ∈ dom (β • γ). Then x ∈ dom (β • γ) ∩ dom ((α • β) • (α • γ)). Thus ((β • γ) • ((α • β) • (α • γ)))(x) = (β • γ)(x) · ((α • β) • (α • γ))(x) = (β • γ)(x) · 0 = 0 ((UP-3)) = O(x). Case 2: x ∈ domα. A. Iampan, P. Mosrijai, A. Satirad / Eur. J. Pure Appl. Math, 11 (3) (2018), 876-881 880 Case 2.1: x /∈ domβ. Then x ∈ domα− domβ, so (β • γ)(x) = 0 and (α • β)(x) is not defined. Thus x /∈ dom (α • β), so ((α • β) • (α • γ))(x) = 0. Thus x ∈ dom (β • γ) ∩ ((α • β) • (α • γ)), so ((β • γ) • ((α • β) • (α • γ)))(x) = (β • γ)(x) · ((α • β) • (α • γ))(x) = 0 · 0 = 0 ((UP-2)) = O(x). Case 2.2: x ∈ domβ. If x /∈ dom γ, then x ∈ domβ − dom γ. Thus (β • γ)(x) is not defined, so x /∈ dom (β •γ). Thus ((β •γ)• ((α•β)• (α•γ)))(x) = 0 = O(x). If x ∈ dom γ, then we conclude that ((β • γ) • ((α • β) • (α • γ)))(x) = (β • γ)(x) · ((α • β) • (α • γ))(x) = (β • γ)(x) · ((α • β)(x) · (α • γ)(x)) = (β(x) · γ(x)) · ((α(x) · β(x)) · (α(x) · γ(x))) = 0 = O(x). Hence, (β • γ) • ((α • β) • (α • γ)) = O, so (UP-1) is holding. Let α ∈ P (X) and let x ∈ X. Case 1: x /∈ domα. Then x ∈ domO − domα. Thus α(x) and (O • α)(x) are not defined. Case 2: x ∈ domα. Then x ∈ domO ∩ domα. Thus (O • α)(x) = O(x) · α(x) = 0 · α(x) = α(x). Hence, O • α = α, so (UP-2) is holding. Let α ∈ P (X) and let x ∈ X. Case 1: x /∈ domα. Then (α •O)(x) = 0 = O(x). Case 2: x ∈ domα. Then x ∈ domα ∩ domO. Thus (α • O)(x) = α(x) · O(x) = α(x) · 0 = 0 = O(x). Hence, α •O = O, so (UP-3) is holding. Let α, β ∈ P (X) be such that α • β = O and β • α = O. Let x ∈ X. Then (α • β)(x) = O(x) = 0 and (β • α)(x) = O(x) = 0. If x ∈ domα− domβ, then (α • β)(x) is not defined which is a contradiction. If x ∈ domβ − domα, then (β • α)(x) is not defined which is a contradiction. If x ∈ domα ∩ domβ, then 0 = (α • β)(x) = α(x) · β(x) and 0 = (β • α)(x) = β(x) · α(x). By (UP-4), we have α(x) = β(x). If x /∈ domα and x /∈ domβ, then α(x) and β(x) are not defined. Hence, α = β, so (UP-4) is holding. Therefore, (P (X), •, O) is a UP-algebra. Theorem 3. T (X) is a UP-ideal of P (X) and we shall call it the full transformation UP-algebra induced by a UP-algebra X. REFERENCES 881 Proof. Clearly, O ∈ T (X). Let α, β, γ ∈ P (X) be such that α • (β • γ) ∈ T (X) and β ∈ T (X). Then dom (α • (β • γ)) = X and domβ = X and so by (2.1), X = dom (α • (β • γ)) = (domα − dom (β • γ)) ′ . Thus domα − dom (β • γ) = ∅ and so by (2.1), ∅ = domα − dom (β • γ) = domα − (domβ − dom γ) ′ = domα − (X − dom γ) ′ = domα−((dom γ) ′ ) ′ = domα−dom γ. By (2.1), dom (α•γ) = (domα−dom γ) ′ = ∅′ = X. That is, α • γ ∈ T (X). Hence, T (X) is a UP-ideal of P (X) and also a UP-filter and a UP-subalgebra. Acknowledgements The authors wish to express their sincere thanks to the referees for the valuable sug- gestions which lead to an improvement of this paper. References [1] T. Guntasow, S. Sajak, A. Jomkham, and A. Iampan. Fuzzy translations of a fuzzy set in UP-algebras. J. Indones. Math. Soc., 23(2):1–19, 2017. [2] A. Iampan. A new branch of the logical algebra: UP-algebras. J. Algebra Relat. Top., 5(1):35–54, 2017. [3] A. Iampan. UP-algebras: the beginning. COPY HOUSE and PRINTING, Thailand, 2018. [4] D. A. Romano. 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