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Stable moduli spaces of odd-dimensional manifold triads

João Lobo Fernandes

TL;DR

This work extends the stable moduli-space program of Galatius and Randal-Williams to odd-dimensional manifold triads with fixed vertical boundary, introducing a boundary-connected-sum stabilization by $V_g$ and a Moore–Postnikov $n$-factorization framework for tangential data. The main result identifies the stabilized moduli space of $ abla$-structures on a triad with the homotopy orbit of the infinite-loop Thom spectrum $\mathbf{MT}\Theta_N$, via an acyclic map onto a path component of $\Omega^{\infty}\mathbf{MT}\Theta_N$. A Kreck-type stable classification for odd triads follows, linking stable diffeomorphism types to stable normal $n$-types and Euler characteristics. The paper develops a comprehensive cobordism-category toolkit with boundary, refined surgery arguments, and a group-completion strategy, culminating in a flexible general theorem for $\\Theta$-structures and a suite of examples, including reductions to existing even-dimensional results. Overall, the results provide a robust odd-dimensional analogue of the GRW program, with broad implications for the homotopy type of diffeomorphism classifying spaces and stable diffeomorphism classifications in the presence of boundary data.

Abstract

We establish a homotopy-theoretic description of the homology of stable moduli spaces of $(2n+1)$-dimensional manifold triads $(N, \partial^h N, \partial^v N)$ with fixed $\partial^v N$, whenever $n \geq 3$ and $(N, \partial^h N)$ is $1$-connected. Stabilization is performed by taking boundary connected sum with $S^n \times D^{n+1}$. This is an analog of earlier work of Galatius and Randal-Williams for even-dimensional manifolds with fixed boundary, and it extends a previous result by Botvinnik and Perlmutter. As a byproduct, we obtain an analog for odd-dimensional triads of Kreck's stable diffeomorphism classification of even-dimensional manifolds.

Stable moduli spaces of odd-dimensional manifold triads

TL;DR

This work extends the stable moduli-space program of Galatius and Randal-Williams to odd-dimensional manifold triads with fixed vertical boundary, introducing a boundary-connected-sum stabilization by and a Moore–Postnikov -factorization framework for tangential data. The main result identifies the stabilized moduli space of -structures on a triad with the homotopy orbit of the infinite-loop Thom spectrum , via an acyclic map onto a path component of . A Kreck-type stable classification for odd triads follows, linking stable diffeomorphism types to stable normal -types and Euler characteristics. The paper develops a comprehensive cobordism-category toolkit with boundary, refined surgery arguments, and a group-completion strategy, culminating in a flexible general theorem for -structures and a suite of examples, including reductions to existing even-dimensional results. Overall, the results provide a robust odd-dimensional analogue of the GRW program, with broad implications for the homotopy type of diffeomorphism classifying spaces and stable diffeomorphism classifications in the presence of boundary data.

Abstract

We establish a homotopy-theoretic description of the homology of stable moduli spaces of -dimensional manifold triads with fixed , whenever and is -connected. Stabilization is performed by taking boundary connected sum with . This is an analog of earlier work of Galatius and Randal-Williams for even-dimensional manifolds with fixed boundary, and it extends a previous result by Botvinnik and Perlmutter. As a byproduct, we obtain an analog for odd-dimensional triads of Kreck's stable diffeomorphism classification of even-dimensional manifolds.
Paper Structure (27 sections, 48 theorems, 62 equations, 2 figures)

This paper contains 27 sections, 48 theorems, 62 equations, 2 figures.

Key Result

Theorem 1

Let $(N,\partial^h N,\partial^v N)$ be a compact smooth $(2n+1)$-dimensional manifold triad where $N$ is connected, $(N,\partial^h N)$ is $1$-connected, $\partial^{hv} N\neq \emptyset$, and $n\geq 3$. For a Moore--Postnikov $n$-factorization $\tau_N=\Theta_N\circ l_N$, the map is acyclic onto the path component it hits.

Figures (2)

  • Figure 1: This is a triad cobordism $(W, \partial^h W,\partial_1 W, \partial^v W)$ from $(M,\partial^h M,\partial^v M)$ to $(N,\partial^h N,\partial^v N).$
  • Figure 2: This is a triad cobordism $W:M\leadsto N$ obtained from the trivial triad cobordism $(M\times [0,1],\partial^h M\times [0,1], \partial^v M\times [0,1], M\times \{0,1\})$ by attaching a left $k$-handle to $M\times \{1\}$. On the other hand, it is obtained from the trivial cobordism $N\times [0,1]$ by attaching a right $(d-k)$-handle to $N\times \{0\}$ (compare with \ref{['dual handle']}). We also depict the attaching map $f$, belt sphere $f'$ (see \ref{['elementary cobordisms']}), the core $(D^k_+,\partial_0D^k_+)$ and cocore $D^{d-k}.$

Theorems & Definitions (116)

  • Theorem 1
  • Remark
  • Theorem 2: \ref{['final with null']}
  • Corollary 3: Stable diffeomorphism classification
  • Definition 2.1.1
  • Remark 2.1.2
  • Lemma 2.1.3: 2 out of 3
  • proof
  • Lemma 2.1.4: Pushouts
  • proof
  • ...and 106 more