Search arXivSearch

arXiv · 2603.22199

Weil restriction, normal bundles and motivic Thom spaces

Abstract

Recent developments in motivic homotopy theory, particularly the construction of norm functors by Bachmann and Hoyois, have revealed deep connections between algebraic geometry and homotopy-theoretic structures. In this paper, we investigate certain geometric aspects of norm functors through the Weil restriction of schemes, which underlies these constructions. We show that Weil restriction preserves vector bundles and extend existing results concerning normal bundles. We then relate the Weil restriction to norm functors and, using a result of Bachmann and Hoyois, establish its compatibility with motivic Thom spaces. Finally, in the setting of motivic cohomology with rational coefficients, we prove that the Weil restriction map agrees with the norm map induced by a norm functor and that it preserves Thom classes.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Guangzhao Zhu. 2026-05-29. Weil restriction, normal bundles and motivic Thom spaces. https://arxiv.org/abs/2603.22199

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Lawson--Deligne Classes and Applications

We construct the integral Lawson--Deligne map of weight $q=n-p-k-1$ on smooth complex projective $n$-folds using filtered currents. It lifts the Friedlander--Mazur cycle class, recovers the reduced generalized Abel--Jacobi invariant on homologically trivial classes, and is compatible with algebraic correspondences. A Picard--Fuchs separation argument applied to the conic and van Geemen normal functions on the mirror quintic determines explicit regulator subspaces modulo the full rational period group. For prescribed elliptic moduli and a suitable mirror-quintic fiber, the subspace generated by their $a$- and $b$-loop products has dimension twice the $\Q$-dimension of the period-monomial space. Moduli $i\sqrt{\ell_j}$ for distinct primes $\ell_j$ give $2^{k+1}$ independent images on varieties of dimension $p+k+2$; one repeated imaginary quadratic modulus gives dimension four for every $k\geq1$. Compatibility with known projective-bundle and blow-up decompositions yields independent exceptional subspaces on smooth rational varieties. We also compare the higher Chow composite with the Bloch--KLM regulator after lowering the Hodge filtration. The KLM representative reduces to a cut-current class, and equality with the Lawson composite is proved in degree zero and for constant-unit decomposable classes. The general positive-degree comparison is reduced to an explicit filtered-realization condition.

math.AG

Complete quasimaps to $\mathsf{Bl}_{\mathbb{P}^s}(\mathbb{P}^r)$

We introduce a moduli space of ``complete quasimaps'' to $\mathsf{Bl}_{\mathbb{P}^s}(\mathbb{P}^r)$. The construction, following previous work for curves on projective spaces, essentially proceeds by blowing up Ciocan-Fontanine--Kim's space of quasimaps at loci where sections of line bundles are linearly dependent. We conjecture that tautological intersection numbers on these moduli spaces give enumerative counts of curves of fixed complex structure on $X$ subject to general incidence conditions, in contrast with traditional compactifications of the moduli spaces of maps. A result of Farkas guarantees that these spaces are pure of expected dimension. The conjecture is proven in dimension 2, where the main input is a Brill-Noether theorem for general curves on toric surfaces.

math.AG