Partial order relations, on boolean algebra

In summary: Therefore, the relation '≤' on a boolean algebra B is a partial order relation. In summary, we have shown that the relation '≤' is reflexive, antisymmetric, and transitive, which means it is a partial order relation.
  • #1
buchi
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I am a bit confused about a question on proving partial order relation. here is the question and what i done so far.

"define the relation '≤' on a boolean algebra B by
for all x,yεB x≤y if and only if xVy=y, show that '≤' is a partial order relation"

first of all what exactly does boolean algebra B look like? can you give me an example of a set A that is a boolean algebra?

I have done a lot of examples to prove equivalence relation last week and the idea is straight forward and with this one I first tried to prove reflexivity antisymmetry and transitive



reflexivity:
for any element x that is in B x≤x that is xVx=x? this part doesn't make sense to me nor do I know what does xVx mean x or x as a set operation 'OR' if so could you guys lead me in a bit

I think once i understand what exactly xVy=y means and how i can manupulate it i think i will be ok to prove antisymmetry transitivity and reflexivity

thanks guys


thanks in advance
 
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  • #2
A boolean algebra is a set A that is closed under the operations of union (∪), intersection (∩), and complement (ˉ). As an example, consider the set A = {a,b,c,d}. Then A is a boolean algebra because it is closed under the operations of union, intersection and complement. To prove reflexivity for this relation, we need to show that for any element x in B, x ≤ x. Since xVy=y, this means that if x is equal to y, xVy must be equal to y. Hence, for any element x in B, xVx=x and so x ≤ x, which proves that the relation is reflexive. To prove antisymmetry, we need to show that for any elements x, y in B, if x ≤ y and y ≤ x, then x must be equal to y. Since xVy=y, this means that if x is equal to y, xVy must be equal to y. Hence, if x ≤ y and y ≤ x, then xVy must be equal to both x and y. This implies that x must be equal to y, which proves that the relation is antisymmetric.Finally, to prove transitivity, we need to show that for any elements x, y, z in B, if x ≤ y and y ≤ z, then x ≤ z. Since xVy=y and yVz=z, this means that if x is equal to y and y is equal to z, then xVz must be equal to z. Hence, if x ≤ y and y ≤ z, then xVz must be equal to z, which proves that the relation is transitive.
 

1. What is a partial order relation?

A partial order relation is a mathematical concept that defines a relationship between elements of a set in which some elements are "greater than" or "less than" others, but not necessarily comparable. This means that some elements may be equal, and some may not have a defined relationship with each other.

2. How is a partial order relation represented?

In boolean algebra, a partial order relation is typically represented using a Hasse diagram, which is a visual representation of the relationship between elements in a partially ordered set. It is also possible to represent a partial order relation using a matrix or a directed graph.

3. What are the properties of a partial order relation?

A partial order relation must satisfy three properties: reflexivity, antisymmetry, and transitivity. Reflexivity means that every element is related to itself, antisymmetry means that if two elements are related, they must be equal, and transitivity means that if A is related to B and B is related to C, then A is related to C.

4. How is a partial order relation different from a total order relation?

A total order relation is a special case of a partial order relation in which all elements are comparable. This means that for any two elements in a totally ordered set, one is always greater than or equal to the other. In a partial order relation, some elements may not have a defined relationship with each other.

5. What are some real-life examples of partial order relations?

Partial order relations can be found in many real-life situations, such as ranking systems, where some items may be equal in rank or not comparable. They are also used in computer science, specifically in databases, to define relationships between data. Another example is in scheduling tasks, where some tasks may have a defined order, but others may be interchangeable.

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