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Incompressible Porous Media Equation


The incompressible porous media equation, abbreviated IPM equation, transports a scalar field rho representing density by the divergence-free Darcy velocity u(rho) that it generates. On the two-dimensional torus, the forced equation can be written

(partialrho)/(partialt)+u(rho)·del rho=F
(1)
del ·u(rho)=0,
(2)

where u is a zero-order linear operator specified through the Fourier transform by Darcy's law. It is an active-scalar model for the motion of incompressible fluids through porous media.

Córdoba and Martínez-Zoroa (2024) proved finite-time blow-up from smooth initial data on R^2 with a force that is smooth in space and bounded in time. Alpöge et al. (2026) claim the corresponding result on T^2 with F smooth jointly in space and time. More precisely, they construct a solution smooth for every t<1 which converges in C^eta for every 0<=eta<1, while

 lim_(t^1)||del rho(t)||_infty=lim_(t^1)||D_xu(rho(t))||_infty=infty.
(3)

Alpöge et al. (2026) report using Claude to reconstruct the earlier argument and Claude and Codex to prepare the manuscript, handle inductive orders and constants, and formalize the argument in Lean under the authors' direction. As of Sep. 16, 2026, the corresponding IPM Lean files had not been publicly released (Buckmaster 2026a), and independent specialist review of the complete argument had not been reported.


See also

Boussinesq System, Finite-Time Blow-Up, Torus

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References

Alpöge, L.; Buckmaster, T.; and Coiculescu, M. P. "Extending the Córdoba-Martínez-Zoroa IPM Blow-Up to Uniformly Space-Time Smooth Forcing." 15 Sep 2026. https://arxiv.org/abs/2609.16470.Buckmaster, T. "fluid_lean." Sep. 8, 2026a. https://github.com/tristanbuckmaster/fluid_lean/tree/d0124689230b58b4f86e7b90ac59de06404b3b6b.Buckmaster, T. "Statement." Sep. 8, 2026b. https://cims.nyu.edu/~tristanb/statement.pdf.Córdoba, D. and Martínez-Zoroa, L. "Finite Time Singularities of Smooth Solutions for the 2D Incompressible Porous Media (IPM) Equation with a Smooth Source." 21 Oct 2024. https://arxiv.org/abs/2410.22920.

Cite this as:

Weisstein, Eric W. "Incompressible Porous Media Equation." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/IncompressiblePorousMediaEquation.html

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