I think above sentence should be removed: we already have descriptions for numerator/denominator attributes. This will be a third time. Also, notion of denominator clash with denominator argument name in surrounding sentences. Last, but not least: readers can think, that our internal representation of the Fraction is like described. While it's true - this is an implementation detail.

@AA-Turner, please don't merge this. Lets wait for a second approval from @serhiy-storchaka or @picnixz.

This will be a third time.

In total, yes, but the first and only within the constructor. We have seen from analytics and annecdotal evidence that when looking for reference documentation, readers generally only look at the relevant function/class/method, rather than following links or looking elsewhere. Here, the repetition helps, not hinders.

Last, but not least: readers can think, that our internal representation of the Fraction is like described. While it's true - this is an implementation detail.

I'm not sure I follow. Could you elaborate?

I concur with @skirpichev. This sentence is redundant here, it will only confuse users.

When you say "The numerator and denominator of this new instance are converted" you refers to the numerator and denominator attributes. Since there is no any mark up, it can be confused with constructor parameters. If you add links, this will be just a repetition of what was referenced.

The point is not that this sentence can be interpreted in correct way (if you already know how it all works), but that it can be interpreted incorrectly, and it is easy to misinterpret it on first reading.

Do you have a suggested rewording? I remain of the opinion that we should mention this in the documentation for the constructor, rather than indirectly through attribute documentation.

This sentence is redundant here, it will only confuse users.

Does the rest looks ok?

Since there is no any mark up, it can be confused with constructor parameters.

(As a side note, I don't think it's a good idea if we will distinguish different meanings just by markup.)

I'm not sure I follow. Could you elaborate?

Rational numbers are just a set of ordered pairs of integers with some equivalency relation. Any such equivalent pair can be used to represent a rational number. So, on which numerator/denominator you are talking here? Are you saying that Fraction internally represented by a canonical representative (in lowest terms and with a positive denominator)? Or that attributes of the Fraction instance returns that canonical representative?

Why is it needed? In what cases the user needs such information?

I concur with @skirpichev. This sentence is redundant here, it will only confuse users.

When you say "The numerator and denominator of this new instance are converted" you refers to the numerator and denominator attributes. Since there is no any mark up, it can be confused with constructor parameters. If you add links, this will be just a repetition of what was referenced.

The point is not that this sentence can be interpreted in correct way (if you already know how it all works), but that it can be interpreted incorrectly, and it is easy to misinterpret it on first reading.