3) If where are distinct primes,
In how many ways can n be expressed as a product of 2 positive integers?
( are considered the same)
What is the answer if ?
From the solution, they mentioned the number of ways to choose a is which i understand.
It is stated that "it is a duplication by a factor of 2 since and both appear
as subsets but they give the same factorisation".
I do not understand where the duplication is.
Can somehow show me an example?
With three factors to choose from, there are: possible subsets.
They are: .
But the question is: how many two-set partitions are there?
There are four: .
The partition is the same as
. . because are the same factoring.