This is a repeat of the first section but with numbers in theorem heads
swapped to the left.
Ahlfors' Lemma gives the principal criterion for obtaining lower bounds
on the Kobayashi metric.
Ahlfors' Lemma 2
Let
ds2 = h(z)dz be a Hermitian pseudo-metric on
Dr,
h∈C2(Dr), with ω the associated
(1, 1)-form. If
Ric ω≥ω on
Dr,
then
ω≤ωr on all of
Dr (or equivalently,
ds2≤dsr2).
Lemma 2.1 (negatively curved families)
Let
{ds12,..., dsk2} be a negatively curved family of metrics
on
Dr, with associated forms ω1, ..., ωk.
Then
ωi≤ωr for all i.
Then our main theorem:
Theorem 2.1
Let dmax and dmin be the maximum, resp. minimum distance
between any two adjacent vertices of a quadrilateral Q. Let σ
be the diagonal pigspan of a pig P with four legs.
Then P is capable of standing on the corners of Q iff
σ≥.
|
(2) |
Corollary 2.2
Admitting reflection and rotation, a three-legged pig P is capable of
standing on the corners of a triangle T iff () holds.