Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1-Deterimine which of the following are equivalence relations and/or partia orde

ID: 2963343 • Letter: 1

Question

1-Deterimine which of the following are equivalence relations and/or partia ordering relations for the given sets:

a- A={Lines in the plane}; x r y if and only if x is parallel to y.


b- A=R; if and only if x is parallel to y. (where R is real numbers)


2- For the set of cities on a map, consider the relation x r y if and only if city x is connected by a city y. A city is considered to be connected to itself, and two cities are connected even though there are cities on the road between them. Is this an equivalence relation or a partial ordering? Explain?

Explanation / Answer

1

a) A is an Equivalence Relation

Reflexive : x is parallel to itself => x R x

Symmetric : x is parallel to y => y is parallel to x.

Therefore x R y => y R x

Transitive : x is parallel to y and y is parallel to z then x, y, z are parallel to each other.

=> x R y and y R z => x R z

Therefore A is equivalent.


2

It is an Equivalence Relation.

Reflexive : x is connected to itself (Given) => x R x

Symmetric : x is connected to y => y is connected to x as two cities are inter-connected.

=> x R y => y R x

Transitive : As it is given that two cities are connected even if there are cities in between, we say that if x is connected to y and y is connected to z then x is connected to z.

=> x R y and y R z => x R z