arXiv subjects

Haruo Minami

Publications and source records attributed to Haruo Minami.

7 recordsLinked to original sources

arXiv2025

On homotopy elements represented by quotients of Lie groups

Consider the quotient $G/B$ of a simple matrix Lie group $G$ by a subgroup $B$ isomorphic to a direct product of some of $S^1$s and $S^3$s such that its adjoint representation can be extended over $G$. Then it naturally inherits a stable framing from a twisted left invariant framing $\mathscr{L}^\alpha$ of $G$ where $\alpha$ is the realization of a complex representation of $G$. In this note we want to add some homotopy elements represented by such quotient framed manifolds to those presented in a table of [E. Ossa 1982].

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arXiv2025

$e$-invariants of quotients of Lie groups

Let $G$ be a simply connected compact Lie group and $\mathscr{L}$ be the left invarinat framing of $G$. Let $\mathcal{L}^\lambda$ be the framing obtained by twisting $\mathscr{L}$ by a faithful representation $\lambda$. Given a torus subgroup $T''$ of $G$ we have a framing $(\mathcal{L}^\lambda)_{T''}$ of the quotient $G/T''$ induced from $\mathcal{L}^\lambda$. In this note we show that under a certain dimensional condition the $e_\mathbb{C}$-invariant of $G/T''$ with this framing provides a generator of the $J$-homomorphism or twice that. Thereby we also give a unified proof of the results for $SU(2n)$, $Spin(4n+1)$ and $Spin(8n-2)$ $(n\ge 1)$ previously proved.

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arXiv2025

The groups $Sp(4n+1)$ and $Spin(8n-2)$ as framed manifolds

We consider a compact Lie group as a framed manifold equipped with the left invarianat framing $\mathscr{L}$. In a previous paper we have proved that the Adams $e_\mathbb{C}$-invariant value of $SU(2n)$ $(n\ge 2)$ gives a generator of the image of $e_\mathbb{C}$ by twisting $\mathscr{L}$ by a certain map. In this note we show that in a similar way we can obtain analogous results for $Sp(4n+1)$ and $Spin(8n-2)$ $(n\ge 1)$.

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arXiv2024

Non-null framed bordant simple Lie groups

Let $G$ be a compact simple Lie group equipped with the left invariant framing $L$. It is known that there are several groups $G$ such that $(G, L)$ is non-null framed bordant. Previously we gave an alternative proof of these results using the decomposition formula of its bordism class into a Kronecker product by E. Ossa. In this note we propose a verification formula by reconsidering it, through a little more ingenious in the use of this product formula, and try to apply it to the non-null bordantness results above.

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arXiv2024

The special unitary groups $SU(2n)$ as framed manifolds

Let $[SU(2n), \mathscr{L}]$ denote the bordism class of $SU(2n)$ $(n\ge 2)$ equipped with its left invariant framing $\mathscr{L}$. Then it is well known that $e_\mathbb{C}([SU(2n), \mathscr{L}])=0$ where $e_\mathbb{C}$ denotes the complex Adams $e$-invariant. In this note we show that replacing $\mathscr{L}$ by the framing obtained by twisting it by a specific map the zero value of $e_\mathbb{C}([SU(2n), \mathscr{L}])$ can be transformed into a generator of $\mathrm{Im} \, e_\mathbb{C}$ which is isomorphic to a cyclic group. In addition we show that the same procedure affords an analogous result for a quotient of $SU(2n+1)$ by a circle subgroup which inherits a canonical framing from $SU(2n+1)$ in the usual way. .

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arXiv2022

A remark on a proof of $[G, L]=0$ for a Lie group $G$

In this note we give an improvement of our proof of $[G, L]=0$ for a compact framed Lie group $(G, L)$, which depends heavily on the choice of a circle subgroup $S\subset G$. We attempt here to make a more suitable choice of this circle subgroup.

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arXiv2021

A note on the divisibility of the Whitehead square

We show that if we suppose n>3 and the (2n-1)-stem in the stable homotopy groups of spheres has no 2-torsion, then the Whitehead squares of the identity maps of (2n+1) and (4n+3)-spheres are divisible by 2. Applying the result of G. Wang and Z. Xu on the 61-stem in the stable homotopy groups of spheres, we find that the Kervaire invariant one elements in dimensions 62 and 126 exist.

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