Outer Automorphisms and the Jacobian
نویسندگان
چکیده
A graphs of rank n (homotopy equivalent to a wedge of n circles) without “separating edges” has a canonical n-dimensional compact C manifold thickening. This implies that the canonical homomorphism φ : Out(Fn) → GL(n,Z) is trivial in rational cohomology in the stable range answering a question raised in [6]. Another consequence of the construction is the existence of higher Reidemeister torsion invariants for IOut(Fn) = kerφ. These facts were first proved in [8] using different methods.
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