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archipelago
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Unoriented cobordism of oriented manifold
Chapter IX in Stong's "Notes on Cobordism Theory".
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Stable homology of general linear groups
Dwyer's paper is about homological stability. It does not contain a computation of a stable homology group.
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"Inclusion" between higher categories of framed bordisms?
What is your definition of ``equivalence onto its image''?
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Classifying abelian (but non-central) group extensions using homotopy theory
The map $BAut(BA)\rightarrow BAut(A)$ is given by the action on $\pi_1(BA)$. Note that $A$ is abelian, so $\pi_1(BA)$ is functorial in unpointed maps.
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Classifying abelian (but non-central) group extensions using homotopy theory
Now one can compute $BAut(K(A,1))\simeq K(A,2)_{hAut(A)}$ and under this equivalence those fibrations whose monodromy over the basepoint agrees with the given action correspond to those pointed maps $BG\rightarrow K(A,2)_{hAut(A)}$ that induce the given action on fundamental groups.
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Classifying abelian (but non-central) group extensions using homotopy theory
$H^2(G;A)$ is the group of pointed homotopy classes of maps $BG\rightarrow K(A,2)_{hAut(A)}$ that induce the given action $G\rightarrow Aut(A)$ on fundamental groups (here the h-subscript denotes homotopy orbits). Fibrations over $BG$ with fibre $BA\simeq K(A,1)$ and an identification of the fibre over a fixed basepoint are classified by pointed maps $BG\rightarrow BhAut(K(A,1))$ where $Aut(K(A,1))$ is the topological monoid of self-homotopy-equivalences of $K(A,1)$.
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Spectral sequence construction of Euler class of group extension
Yes, up to a sign. This is a special case of Theorem 4 on p. 133 of Hochschild—Serre‘s ‘Cohomology of group extensions‘.
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The image of the J-homomorphism of the tangent bundle of the sphere
The relation follows from the discussion in Section 2 of James' "On the iterated suspension''.
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Monodromy action on homogeneous spaces
The fundamental group of the base of a fibre sequence acts on the fibre over the basepoint in the \emph{unpointed} homotopy category, so in general there is no induced action on the homotopy groups. The fundamental group of the total space however acts on the fibre in the \emph{pointed} homotopy category, and thus in particular on its homotopy groups. In your example, the action of $\pi_1(BG)=\pi_0(G)$ on $G/H$ is indeed given by left-translation, which is not pointed, but can be enhanced to a pointed action once one restricts it to $\pi_0(H)$ since $[1] \in G/H$ is now preserved.
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How to learn homotopy theory
That book has a second author.
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Poincaré duality
Less fancy, classical Lefschetz duality gives $H^q(M)\cong H^q(\overline{M})\cong H_{n-q}(\overline{M},\partial \overline{M})\cong \widetilde{H}_{n-q}(\overline{M}/\partial \overline{M})\cong \widetilde{H}_{n-q}(M^+)$.
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Relative version of Browder's theorem on H-spaces
$X=K(\mathbb{Z},2)$ is a counterexample to your first paragraph. Did you forget an assumption?
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