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Generators and relations of the Cremona group in dimension three

Determine a complete presentation—namely, a generating set together with defining relations—for the Cremona group Bir(P^3) of birational self-maps of complex projective 3-space. Establish whether Bir(P^3) admits a finite generating set and identify explicit relations among the generators to give a full group presentation.

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Background

In dimension two, the classical Noether–Castelnuovo theorem states that the Cremona group Bir(P2) is generated by PGL(3,C) together with the standard Cremona transformation. This gives a concrete and complete description of Bir(P2) in terms of generators.

The authors note that extending such a presentation to higher dimensions is difficult. In particular, identifying generators and relations for Bir(P3) remains unresolved. A solution would provide a foundational understanding of birational transformations in three dimensions, with implications across algebraic geometry and areas where birational dynamics play a role (e.g., integrable systems and algebraic dynamics).

References

It is worth mentioning that in dimension higher than two, the problem of finding generators and relations of \Bir(Pn) is highly non-trivial and still open already for P3.

Classical Algebraic Geometry and Discrete Integrable Systems (2510.12647 - Alecci et al., 14 Oct 2025) in After Theorem (Noether–Castelnuovo), Subsection “Rational maps”, Section 1 (Algebraic geometry)