Computer assisted proofs of two-dimensional attracting invariant tori for ODEs

This work studies existence and regularity questions for attracting invariant tori in three dimensional dissipative systems of ordinary differential equations. Our main result is a constructive method of computer assisted proof which applies to explicit problems in non-perturbative regimes. We obtain verifiable lower bounds on the regularity of the attractor in terms of the ratio of the expansion rate on the torus with the contraction rate near the torus. We consider separately two important cases of rotational and resonant tori. In the rotational case we obtain Cᵏ lower bounds on the regularity of the embedding. In the resonant case we verify the existence of tori which are only C⁰ and neither star-shaped nor Lipschitz.