1547845439-The_Ricci_Flow_-_Techniques_and_Applications_-_Part_I__Chow_

(jair2018) #1

400 8. APPLICATIONS OF THE REDUCED DISTANCE


we have l·l~(T) s eCoT l·l~(To) = e^00 T l·l~(o) acting on vector fields for T E


[To - T /2, To]. We can estimate [, (f3) as follows:
[, (f3)

S {To VT (Rg( 7 ) (f3(T))+Id1


2
) dT
~-T~ TgW

s -2 ( T3/2 3/2) GT 1To. ;::; I d/312
0 - (To - T /2) sup Rg(t) + e

(^0) v T -d dT
3 Mx[O,T/2] To-T/2 T g(O)


= ~ (T~/2 - (To -T/2)3/2) ( sup R9(t) + 4eCoT (d9(0) (q, qo))2)

3 Mx[O,T/2] T^2

~ T3/2 ( G 4eCoT r5)
s3 no+ T2.

Let a : [O, To - T /2] --+ M be a minimal £-geodesic with a (0) =Po and
a (To -T/2) = qo. Then


£(a)= 2VTo -T/2 · £ (qo, To -T/2) s nylT/2.


Consider the concatenated path:

'Y (T) =(a'-" f3) (T) = { a (T) if t E [O, To -T/2],


. f3(T) iftE[To-T/2,To].

This path is well defined and piecewise smooth. We have


1 1
£ (q, To) s f1f!"£ (!') = fFT1""" [£(a)+£ (f3)]
2vTo 2vTo

s ~ [nVT/2 + ~T


3
1

2
( nCo +

4

e~~r5) J


~ C1 (ro, n, T, sup. Re g(t)).

Mx[O,T/2]

(ii) Choosing ro = ri in (i), we have

V (To)= JM (47rTo)-nl^2 e-£(q,To)dμg(O) (q)


2: { (47rTo)-n/2 e-£(q,To)dμ9(0) (q)
j B9(0) (qo,ri)

2: { (47rTo)-n/2 e-C1dμ9(0) (q)
} B9(0) (qo,r1)

2: v1 ( 47rT)-nl^2 e-Ci ~ C2 (v1, ri, n, T, sup Re g(t)).
Mx[O,T/2]
D
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