Abstract
We report on our investigations concerning algebraic and transcendental Brauer–Manin obstructions to integral points on complements of a hyperplane section in degree four del Pezzo surfaces. We discuss two concepts of an obstruction at an archimedean place. Concrete examples are given of pairs of non-homogeneous quadratic polynomials in four variables representing (0, 0) over Q and over Z p for all primes p, but not over Z. By blow-up, these yield cubic polynomials in three variables all integral solutions of which satisfy a gcd condition.
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All computations are with magma [BCP].
The second author was supported by the NSF under agreement No. DMS-1128155 and by an NWO grant 016.Veni.173.016.
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Jahnel, J., Schindler, D. On integral points on degree four del Pezzo surfaces. Isr. J. Math. 222, 21–62 (2017). https://doi.org/10.1007/s11856-017-1581-0
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DOI: https://doi.org/10.1007/s11856-017-1581-0