The p-widths of $RP^2$
Jared Marx-Kuo
TL;DR
This work determines the full p-width spectrum for $(\mathbb{R}P^2,g_{std})$. Building on Almgren--Pitts min-max theory and the Chodosh--Mantoulidis approach for $S^2$, it constructs $\mathbb{Z}_2$-invariant sweepouts induced by polynomials on $S^2$ and introduces a perturbation $g_{\mu}$ near $g_{std}$ to control the short geodesics and parity of total multiplicity. The main result shows $\omega_p(\mathbb{R}P^2,g_{std}) = 2\pi \left\lfloor \frac{1}{4}\left(1+\sqrt{1+8p}\right)\right\rfloor$ for all $p$, with widths realized by the designed sweepouts, and it explicitly groups $p$ into blocks where the width is constant, yielding a precise, computable spectrum. The techniques yield a rigidity-type perspective for p-widths on RP$^2$ and highlight the role of $\mathbb{Z}_2$-invariant constructions in quotient geometries.
Abstract
We compute the p-widths, $\{ω_p\}$, for the real projective plane with the standard metric.
