Generalized Diophantine equation and the method of infinite descent

[e2m2a]

TL;DR Summary

Cannot find proof asserted by Wikipedia article on a generalized Diophantine equation

There is an entry in Wikipedia at this link: https://en.wikipedia.org/wiki/Pythagorean_triple
Under elementary properties of primitive Pythagorean triples, general properties,sixth bullet from the bottom of this section, there is this generalized Diophantine equation:
x^2p + y^2p = z^2
Where: p ≥ 2.
The article asserts there is no integer solution to this Diophantine equation for all values of p ≥ 2:
I have a number of questions about this. First, is this assertion true? Second, where can I find the proof for this? There was no citation for a proof. And third, If there is a proof, would it use the method of infinite descent for this generalized expression?

 

[BvU]

sixth bullet from the bottom

• Only two sides of a primitive Pythagorean triple can be simultaneously prime because by Euclid's formula for generating a primitive Pythagorean triple, one of the legs must be composite and even.[20] However, only one side can be an integer of perfect power ${\displaystyle p\geq 2}$ because if two sides were integers of perfect powers with equal exponent ${\displaystyle p}$ it would contradict the fact that there are no integer solutions to the Diophantine equation ${\displaystyle x^{2p}\pm y^{2p}=z^{2}}$, with ${\displaystyle x}, {\displaystyle y},$ and ${\displaystyle z}$ being pairwise coprime.[21]

Make life easier for all by quoting in stead of referring ... I't not a long entry entry in the list
(and some understand first from bottom is one but last )

First, is this assertion true?

I don't understand what assertion you are referring to. The Beal conjecture lemma clearly states that it hasn't been proved or disproved so far. So no wonder there is no citation. And the 'can be simultaneously prime' is on top of that conjecture.

The link says you can earn a million bucks if you can prove or disprove the Beal conjecture

Second, where can I find the proof for this? There was no citation for a proof

$\$

 

[pbuk]

There was no citation for a proof.

Yes there is: click on the blue number 21. The cited paper is available online (search for the title).

 

[e2m2a]

Ok. I will look into it. Thanks. Beal conjecture sounds intriguing.

 

[pbuk]

Make life easier for all by quoting in stead of referring ... I't not a long entry entry in the list
(and some understand first from bottom is one but last )

Thanks for this @BvU - as well as being easier, quoting also avoids the problem of the referenced website changing. @e2m2a please quote instead of linking in future. Also please use $\LaTeX$ in your posts: write $x^{2p} + y^{2p} = z^2$ instead of x^2p + y^2p = z^2 (if you don't know how, reply to this message and you will see how it works in my quoted message).

I don't understand what assertion you are referring to. The Beal conjecture lemma clearly states that it hasn't been proved or disproved so far. So no wonder there is no citation. And the 'can be simultaneously prime' is on top of that conjecture.

The link says you can earn a million bucks if you can prove or disprove the Beal conjecture

I think the OP is referring to the special case of the Beal conjecture quoted above which has been solved (H. Darmon and L. Merel (2007) Winding quotients and some variants of Fermat’s Last Theorem).