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Stably diffeomorphic manifolds and the realisation of modified surgery obstructions

Anthony Conway, Diarmuid Crowley, Mark Powell, Joerg Sixt

Abstract

For every $k \geq 2$ we construct infinitely many $4k$-dimensional manifolds that are all stably diffeomorphic but pairwise not homotopy equivalent. Each of these manifolds has hyperbolic intersection form and is stably parallelisable. In fact we construct infinitely many such infinite sets. To achieve this we prove a realisation result for appropriate subsets of Kreck's modified surgery monoid $\ell_{2q+1}(\mathbb{Z}[π])$, analogous to Wall's realisation of the odd-dimensional surgery obstruction $L$-group $L_{2q+1}^s(\mathbb{Z}[π])$.

Stably diffeomorphic manifolds and the realisation of modified surgery obstructions

Abstract

For every we construct infinitely many -dimensional manifolds that are all stably diffeomorphic but pairwise not homotopy equivalent. Each of these manifolds has hyperbolic intersection form and is stably parallelisable. In fact we construct infinitely many such infinite sets. To achieve this we prove a realisation result for appropriate subsets of Kreck's modified surgery monoid , analogous to Wall's realisation of the odd-dimensional surgery obstruction -group .

Paper Structure

This paper contains 32 sections, 47 theorems, 258 equations.

Key Result

Theorem 1.1

Fix an integer $k \geq 2$. There is a closed, connected oriented, stably parallelisable, smooth $4k$-manifold $M$ with $\pi_1(M) \cong \mathbb{Z}$ and $|\mathcal{S}^{\rm st}_h(M)| = \infty$. Indeed, there are infinitely many stable diffeomorphism classes of such manifolds, $\{[M_i]_{\rm st} \}_{i=1}

Theorems & Definitions (133)

  • Theorem 1.1
  • Theorem 1.2: Wall Realisation
  • Theorem 1.3: Realisation of modified surgery obstructions
  • Remark 1.4
  • Remark 1.5
  • Theorem 1.9
  • Theorem 1.10
  • Lemma 2.1
  • proof
  • Definition 2.2
  • ...and 123 more