Discrete Math - equivalence laws

In summary, an equivalence relation in discrete math is a relation between two elements in a set that satisfies the properties of reflexivity, symmetry, and transitivity. It is typically represented using mathematical notation and can be used to prove properties, simplify equations, and solve problems. An example of an equivalence relation is "congruence modulo n" on the set of integers.
  • #1
Waggattack
4
0
I need to show that P<->Q is logically equivalent to ( P ^ Q ) v ( ~P ^ ~Q)

So far I have P <-> Q is equivalent to ( ~P v Q ) ^ ( ~Q v P ) by a example

I have no idea where to go from here
 
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  • #2
Hi Waggattack! :smile:
Waggattack said:
( ~P v Q ) ^ ( ~Q v P )

Now use the distributive law (ie, expand). :wink:
 
  • #3
Wouldn't a fairly simple "truth table" suffice?
 

1. What is the definition of an equivalence relation in discrete math?

An equivalence relation is a relation between two elements in a set that satisfies three properties: reflexivity, symmetry, and transitivity. This means that for any element x in the set, it is related to itself (reflexivity), if x is related to y then y is also related to x (symmetry), and if x is related to y and y is related to z, then x is also related to z (transitivity).

2. How are equivalence relations represented in discrete math?

Equivalence relations are typically represented using mathematical notation, such as R(x,y) or x ~ y, where x and y are elements in a set and ~ represents the equivalence relation between them.

3. What are the main equivalence laws in discrete math?

The three main equivalence laws in discrete math are the reflexive law, the symmetric law, and the transitive law. These laws define the properties that must be satisfied for a relation to be an equivalence relation.

4. How are equivalence laws used in discrete math?

Equivalence laws are used to prove the properties of a relation and to determine if it is an equivalence relation. They are also used to simplify equations and solve problems involving equivalence relations.

5. Can you give an example of an equivalence relation in discrete math?

One example of an equivalence relation in discrete math is the relation "congruence modulo n" on the set of integers. This relation states that two integers are congruent if their difference is divisible by n. It satisfies all three properties of an equivalence relation, as any integer is congruent to itself, if a is congruent to b then b is congruent to a, and if a is congruent to b and b is congruent to c then a is congruent to c.

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