Let A be a non-empty set, ≃ ⊆ A × A an equivalence realtionship and ⪯ ⊆ A × A a partial order, both over A. Consider the quotient set: A / ≃, and define the following relation ≪ ⊆ (A/ ≃) × (A/ ≃) where (S1, S2) ∈ ≪ if, and only if, there is an a ∈ S1 such that for all b ∈ S2, a ⪯ b. 1.) How to show that ≪r is is a partial order over A/ ≃ where ≪r is the reflex cause of ≪. 2.) Is it true that A has a minimal element according to ⪯ if, and only if, A/ ≃ has a minimal element according to ≪r ? How to show if it is true or false (in such case suggest a counterexample)

Let A be a non-empty set, ≃ ⊆ A × A an equivalence realtionship and ⪯ ⊆ A × A a partial order, both over A. Consider the quotient set: A / ≃, and define the following relation ≪ ⊆ (A/ ≃) × (A/ ≃) where (S1, S2) ∈ ≪ if, and only if, there is an a ∈ S1 such that for all b ∈ S2, a ⪯ b. 1.) How to show that ≪r is is a partial order over A/ ≃ where ≪r is the reflex cause of ≪. 2.) Is it true that A has a minimal element according to ⪯ if, and only if, A/ ≃ has a minimal element according to ≪r ? How to show if it is true or false (in such case suggest a counterexample)

Elements Of Modern Algebra

8th Edition

ISBN:9781285463230

Author:Gilbert, Linda, Jimmie

Publisher:Gilbert, Linda, Jimmie

Chapter1: Fundamentals

Section1.7: Relations

Problem 21E: 21. A relation on a nonempty set is called irreflexive if for all. Which of the relations in...

See similar textbooks

Similar questions

True or False Label each of the following statements as either true or false. Let be an equivalence relation on a nonempty setand let and be in. If, then.
Give an example of a relation R on a nonempty set A that is symmetric and transitive, but not reflexive.
21. A relation on a nonempty set is called irreflexive if for all. Which of the relations in Exercise 2 are irreflexive? 2. In each of the following parts, a relation is defined on the set of all integers. Determine in each case whether or not is reflexive, symmetric, or transitive. Justify your answers. a. if and only if b. if and only if c. if and only if for some in . d. if and only if e. if and only if f. if and only if g. if and only if h. if and only if i. if and only if j. if and only if. k. if and only if.
Let (A) be the power set of the nonempty set A, and let C denote a fixed subset of A. Define R on (A) by xRy if and only if xC=yC. Prove that R is an equivalence relation on (A).
Label each of the following statements as either true or false. If R is an equivalence relation on a nonempty set A, then any two equivalence classes of R contain the same number of element.
12. (See Exercise 10 and 11.) If each is identified with in prove that . (This means that the order relation defined in Exercise 10 coincides in with the original order relation in . We say that the ordering in is an extension of the ordering in .) 11. (See Exercise 10.) According to Definition 5.29, is defined in by if and only if . Show that if and only if . 10. An ordered field is an ordered integral domain that is also a field. In the quotient field of an ordered integral domain define by . Prove that is a set of positive elements for and hence, that is an ordered field. Definition 5.29 Greater than Let be an ordered integral domain with as the set of positive elements. The relation greater than, denoted by is defined on elements and of by if and only if . The symbol is read “greater than.” Similarly, is read “less than.” We define if and only if. As direct consequences of the definition, we have if and only if and if and only if . The three properties of in definition 5.28 translate at once into the following properties of in . If and then . If and then . For each one and only one of the following statements is true: . The other basic properties of are stated in the next theorem. We prove the first two and leave the proofs of the others as exercises.
True or False Label each of the following statements as either true or false. 2. Every relation on a nonempty set is as mapping.
Label each of the following statements as either true or false. Let R be a relation on a nonempty set A that is symmetric and transitive. Since R is symmetric xRy implies yRx. Since R is transitive xRy and yRx implies xRx. Hence R is alsoreflexive and thus an equivalence relation on A.