SUPPOSE A = {a,b,c,d,e,f},and R = {(a,f),(b,e),(c,d),(d,a),(e,b),(f,e)} state with reasons whether the relation is a function from A to A,(II) an everywhere defined function (iii) an onto function (iv) a one to one function

Respuesta :

Answer:

(I) Yes

(II) Yes

(III) No

(IV) No

Step-by-step explanation:

(I) The relation is a function from A to A as it satisfies both existence and uniqueness: every element of A (domain) is related to only one element of A (codomain).

(II) The relation is an everywhere defined function as every element of A is related to an element of A.

(III) The relation is not an onto (surjective) function.

Let's recall the definition of an onto function:

An onto function f : A -> B satisfies: [tex]\forall y \in B : \exists x \in A / f(x)=y[/tex].

In this case, [tex]\nexists x \in A / xRc[/tex]. So, the function is not onto.

(IV) The relation is not a one to one (injective) function.

Let's recall the definition of a one to one function:

A one to one function f : A -> B satisfies: [tex]x \neq y \Rightarrow f(x) \neq f(y)[/tex].

In this case, both [tex]b[/tex] and [tex]f[/tex] relate to [tex]e[/tex], so the function is not one to one.