# Can bilipschitz models of hyperbolic 3-manifolds be made effective?

In their proof of the Ending Lamination Conjecture, Brock, Canary, and Minsky prove existence of bilipschitz models of hyperbolic 3-manifolds (homeomorphic to a surface times $\mathbb{R}$) depending only on the topology and ending invariants of the manifold.

Their proof is non-constructive, so the bilipschitz constants cannot be computed from their proof.
Are the bilipschitz constants close to being computable from their proof? In other words is it "easy" to see what steps in their proof are non-constructive and whether these steps can be made effective?

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## 1 Answer

See Bowditch: link text Systems of bands in hyperbolic 3-manifolds

with an approach to the Brock-Canary-Minsky Theorem (though not through their model manifold) that is, in principle, effective. Though I am not aware of an explicit algorithmic realization.

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I don't know bb's identity, but it's certainly conceivable that he already knows that paper very well... –  HJRW Oct 29 '12 at 10:06