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Ancient Gauss Curvature Flows of Bounded Width

Beomjun Choi, Kyeongsu Choi, Dongjun Noh

TL;DR

This work develops ancient, non-self-similar solutions for curvature-driven flows in 3D: a pancake with flat sides under the Gauss curvature flow and sausage-type ancient solutions for the α-GCF with α>1/2. The authors establish a viscosity-solution framework, derive curvature-ratio evolution on rotationally symmetric profiles, and prove axisial minimality of curvature to enable barrier constructions. They construct the pancake via width-bounded approximations converging to a $C^{1,1}$ ancient solution, and obtain sausage solutions by both small-α barrier methods and large-α translator gluing, ensuring cylinder-like asymptotics and eventual extinction to a round point. These results illuminate flat-side persistence, width control, and asymptotic structures of ancient convex flows, contributing to the classification and behavior of non-self-similar ancient solutions in low dimensions.

Abstract

In this paper, we construct a pancake-like ancient compact solution with flat sides to the Gauss curvature flow, contained in a slab. Also, we construct sausage-like ancient compact solutions to the $α$-Gauss curvature flow with $α>\frac{1}{2}$, asymptotic to a round cylinder.

Ancient Gauss Curvature Flows of Bounded Width

TL;DR

This work develops ancient, non-self-similar solutions for curvature-driven flows in 3D: a pancake with flat sides under the Gauss curvature flow and sausage-type ancient solutions for the α-GCF with α>1/2. The authors establish a viscosity-solution framework, derive curvature-ratio evolution on rotationally symmetric profiles, and prove axisial minimality of curvature to enable barrier constructions. They construct the pancake via width-bounded approximations converging to a ancient solution, and obtain sausage solutions by both small-α barrier methods and large-α translator gluing, ensuring cylinder-like asymptotics and eventual extinction to a round point. These results illuminate flat-side persistence, width control, and asymptotic structures of ancient convex flows, contributing to the classification and behavior of non-self-similar ancient solutions in low dimensions.

Abstract

In this paper, we construct a pancake-like ancient compact solution with flat sides to the Gauss curvature flow, contained in a slab. Also, we construct sausage-like ancient compact solutions to the -Gauss curvature flow with , asymptotic to a round cylinder.

Paper Structure

This paper contains 10 sections, 23 theorems, 104 equations, 4 figures.

Key Result

Theorem 1.1

The Gauss curvature flow in $\mathbb{R}^3$ has an ancient pancake with flat sides, which is a viscosity solution of class $C^{1,1}$.

Figures (4)

  • Figure 1: Ancient pancake
  • Figure 2: Ancient sausage
  • Figure 3: Time slices of paperclip
  • Figure 4: Ancient sausage for $\alpha > 1$

Theorems & Definitions (49)

  • Theorem 1.1: ancient pancake with flat sides
  • Theorem 1.2: ancient sausage
  • Definition 2.1: viscosity solution, c.f. Section 8.2 andrews2000motion, Definition 2.6 choi2022convergence
  • Proposition 2.2: existence of unique solution, Theorem 15 andrews2000motion c.f. Theorem 2.7 choi2022convergence
  • Remark 2.3
  • Lemma 2.4: compactness
  • proof
  • Definition 2.5: displacement
  • Proposition 2.6: c.f. bourni2021collapsing
  • proof
  • ...and 39 more