The (right) homotopy between two A∞-morphisms
Abstract
Let f, g: A→ B be two A∞-morphisms between two A∞-algebras (linear over a commutative ring 𝕂). In this paper, we compare different notions of (right) homotopy between f and g. We note that the A∞-algebra B⊗ R, where R:=𝕂[t,dt], is a model for the interval [0,1]× B in the sense of Fukaya-Oh-Ohta-Ono, and we give a short alternative proof, in the unfiltered case, of the existence of comparison morphisms between such models. We use it to prove that two A∞-morphisms are homotopic à la Seidel if and only if, considered as morphisms of 2-colored DG operads, they are elementary homotopic à la Markl-Shnider-Stasheff through a homotopy which is constant on the two monochromatic parts. We also provide an example of two A∞-morphisms which are elementary homotopic but not weakly equivalent (and so homotopic à la Seidel). Moreover, over a field, we observe that the models for the interval are good path objects in the category of A∞-algebras with (non strict) A∞-morphisms, and we explain why weakly equivalent A∞-morphisms need not be homotopic.
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BibTeX
@misc{ornaghi2026right,
title = {{The (right) homotopy between two A$_\infty$-morphisms}},
author = {Mattia Ornaghi},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.13803},
eprint = {2610.13803},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.13803},
}
RIS
TY - UNPB
TI - The (right) homotopy between two A_∞-morphisms
AU - Mattia Ornaghi
PY - 2026
DA - 2026/10/09
PB - arXiv
DO - 10.48550/arxiv.2610.13803
UR - https://arxiv.org/abs/2610.13803
AB - Let f, g: A→ B be two A_∞-morphisms between two A_∞-algebras (linear over a commutative ring 𝕂). In this paper, we compare different notions of (right) homotopy between f and g. We note that the A_∞-algebra B⊗ R, where R:=𝕂[t,dt], is a model for the interval [0,1]× B in the sense of Fukaya-Oh-Ohta-Ono, and we give a short alternative proof, in the unfiltered case, of the existence of comparison morphisms between such models. We use it to prove that two A_∞-morphisms are homotopic à la Seidel if and only if, considered as morphisms of 2-colored DG operads, they are elementary homotopic à la Markl-Shnider-Stasheff through a homotopy which is constant on the two monochromatic parts. We also provide an example of two A_∞-morphisms which are elementary homotopic but not weakly equivalent (and so homotopic à la Seidel). Moreover, over a field, we observe that the models for the interval are good path objects in the category of A_∞-algebras with (non strict) A_∞-morphisms, and we explain why weakly equivalent A_∞-morphisms need not be homotopic.
ER -