Commit 2024-11-27 13:34 37c90e46
View on Github →feat: uniform time lemma for the existence of global integral curves (#9013) Lemma 9.15 in Lee's Introduction to Smooth Manifolds:
Let
v
be a smooth vector field on a smooth manifoldM
. If there existsε > 0
such that for each pointx : M
, there exists an integral curve ofv
throughx
defined on an open intervalIoo (-ε) ε
, then every point onM
has a global integral curve ofv
passing through it. We only requirev
to be $C^1$. To achieve this, we define the extension of an integral curveγ
by another integral curveγ'
, if they agree at a point inside their overlapping open interval domains. This utilises the uniqueness theorem of integral curves. We need this lemma to show that vector fields on compact manifolds always have global integral curves.