# A nonlinear Lazarev-Lieb theorem: $L^2$-orthogonality via motion planning

## TL;DR

This paper generalizes a result by Lazarev and Lieb on orthogonality of integrable functions using smooth circle-valued functions, employing topological methods and a relaxed motion planning approach.

## Contribution

It provides a lower bound on the equivariant topology of smooth circle-valued functions, extending previous orthogonality results with novel topological techniques.

## Key findings

- Established a lower bound for the equivariant topology of function spaces.
- Generalized Lazarev and Lieb's orthogonality theorem.
- Introduced a relaxed motion planning algorithm with topological implications.

## Abstract

Lazarev and Lieb showed that finitely many integrable functions from the unit interval to $\mathbb{C}$ can be simultaneously annihilated in the $L^2$ inner product by a smooth function to the unit circle. Here we answer a question of Lazarev and Lieb proving a generalization of their result by lower bounding the equivariant topology of the space of smooth circle-valued functions with a certain $W^{1,1}$-norm bound. Our proof uses a relaxed notion of motion planning algorithm that instead of contractibility yields a lower bound for the $\mathbb{Z}/2$-coindex of a space.