Is it normal surface of general type to have infinitely many positive rank elliptic curves?

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Answered at MO.

I am not good at algebraic geometry and almost surely am misunderstanding something.

Got an alleged argument against Bombieri-Lang conjecture and would like to know what the mistake is.

One of the most simplest formulations of Bombieri-Lang conjecture is in Joe Silverman's answer on MO, paraphrasing

...For a surface of general type ... the Bombieri-Lang conjecture says that the solutions in rational numbers ...are.. not Zariski dense (lie on a finite set of curves).

Take the affine surface over the rationals:

$$ z^6 + x^4 - y^2=0$$

According to Magma it is of general type.

Fix $z$ squarefree integer $k$. This gives quartic model of elliptic curve $k^6+x^4-y^2=0$.

This is birationally equivalent to Weierstrass $$v^2=-4k^6u+u^3 $$

As $k$ varies, this gives infinitely many positive rank elliptic curves.

What is wrong with this alleged contradiction?


Comment suggests it might be not of general type.

In Magma online: http://magma.maths.usyd.edu.au/calc/

 K<x,y,z,t>:=ProjectiveSpace(Rationals(),3);
 p:=z^6 + x^4*t^2 - y^2*t^4;
 S:=Surface(K,p);
 KodairaEnriquesType(S);
 KodairaDimension(S);
 //returns:
 // 2 0 General type
 // 2

Added The main misunderstanding was caused by incorrect usage of Magma function. The correct way to check is KodairaEnriquesType(S : CheckADE := true); because of certain assumptions, but this might take much longer.

With this change I get error and no result.