Proving Denumerability of Positive Multiples of Three Greater Than 100

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In summary, the conversation discusses how to show that the set S of positive multiples of three greater than one hundred is denumerable, meaning it can be counted. The solution involves constructing a bijection between the set of natural numbers and S, proving that S is denumerable. The individual asks for confirmation of their solution and the expert confirms that it is correct.
  • #1
eibon
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Homework Statement



Let S be the set of positive multiples of three which are greater than one hundred.
Show that S is denumerable.

Homework Equations


The Attempt at a Solution


let [tex]\phi[/tex]: [tex]N[/tex] [tex]\rightarrow[/tex] S
be given by [tex]\phi[/tex](n)= 99+3n is a bijection
thus it is denumerable

can someone tell me if that is right? if not can you tell me what i did wrong?
 
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  • #2
Why would you think it's not right? It is.
 
  • #3
well its the first time I am taking an math class like this and I am just not sure if I am doing things right
 
  • #4
eibon said:
well its the first time I am taking an math class like this and I am just not sure if I am doing things right

Well, you are doing it right.
 
  • #5
Thanks for the reassurance
 

FAQ: Proving Denumerability of Positive Multiples of Three Greater Than 100

How do you define denumerability?

Denumerability refers to the property of a set to be able to be counted or enumerated. In other words, a set is denumerable if its elements can be arranged in a sequence and each element can be assigned a unique natural number.

What is the significance of proving denumerability of positive multiples of three greater than 100?

Proving the denumerability of a set is important in mathematics as it helps establish the cardinality (size) of the set. In this case, proving the denumerability of positive multiples of three greater than 100 helps us understand the infinite nature of this set and its relationship to other infinite sets.

How can we prove that positive multiples of three greater than 100 are denumerable?

To prove denumerability, we need to show that every element in the set can be paired with a unique natural number. In this case, we can do so by showing that for every natural number n, there exists a positive multiple of three greater than 100 that can be expressed as 3n + 100.

Is there a specific method to prove denumerability or can it be done in multiple ways?

There are different methods for proving denumerability, depending on the set in question. In general, the most common methods involve constructing a bijection (one-to-one correspondence) between the set and the set of natural numbers, or using the diagonalization argument.

Can a set be both denumerable and uncountable?

No, a set cannot be both denumerable and uncountable. A set is either denumerable (countable) or uncountable, as these are two mutually exclusive properties. A set is uncountable if it cannot be put into a one-to-one correspondence with the set of natural numbers.

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