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Connes-Chern Character for Manifolds with Boundary and ETA ...

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CONNES-CHERN CHARACTER AND <strong>ETA</strong> COCHAINS 51<br />

The following <strong>for</strong>mula can easily be shown by induction.<br />

e −tD2 B =<br />

∑n−1<br />

j=0<br />

(−t) j<br />

j!<br />

+ (−t)n<br />

(n − 1)!<br />

(<br />

∇<br />

j<br />

D B) e −tD2 +<br />

∫ 1<br />

0<br />

(1 − s) n−1 e −stD2 (<br />

∇<br />

n<br />

D B ) e −(1−s)tD2 ds.<br />

(5.9)<br />

The identity (5.9) easily allows to prove the following statement about local heat<br />

invariants, cf. [Wid79], [CoMo90], [BlFo90]:<br />

Proposition 5.2. Let A 0 , ..., A k ∈ b Diff(M; W ) of order a 0 , ..., a k . Then the Schwartz<br />

kernel of A 0 e −σ 0tD 2 A 1 e −σ 1tD 2 ...A k e −σ ktD 2<br />

has a pointwise asymptotic expansion<br />

(<br />

A 0 e −σ 0tD 2 A 1 e −σ 1tD 2 ...A k e −σ ktD 2) (p, p)<br />

= ∑ (−t) |α|<br />

σ α 1<br />

0 (σ 0 + σ 1 ) α 2<br />

...(σ 0 + ... + σ k−1 ) αk·<br />

α!<br />

α∈Z k + ,|α|≤n<br />

=:<br />

· (A<br />

0 ∇ α 1<br />

D A 1...∇ α k<br />

D A )<br />

ke −tD2 (p, p) + Op (t (n+1−a−dim M)/2 ),<br />

n∑<br />

j−dim M−a<br />

a j (A 0 , ..., A k , D)(p) t 2 + O p (t (n+1−a−dim M)/2 ),<br />

j=0<br />

(5.10)<br />

∑<br />

where a = k a j . The asymptotic expansion is locally uni<strong>for</strong>mly in p. Furthermore, it<br />

j=0<br />

is uni<strong>for</strong>m <strong>for</strong> σ ∈ ∆ k .<br />

Again we are facing the problem explained be<strong>for</strong>e Theorem 5.1. Still we will be able<br />

to show that one obtains a correct <strong>for</strong>mula by taking the b-trace on the left <strong>and</strong> partie<br />

finie integrals on the right of (5.10):

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