5 It ; 
hy) = = | H\(@) exp(iwt)dw 
h(t1,72) = | | Aoto:.02)explivw in + w2r2)ido a (12.136) 
1 
(250)? 
h3(t1,72, 73) = | | | He. 2,3) expli(@ 171 + W2T2 + W3T3)]dw \dw2dw3. 
1 
(22)? 
The terms H,,(w) are defined as 
H\(@) = iaH\@) 
H>(@1,@2) = i(@ + @2)H2(@1, 2) (12.137) 
H3(@ 1, 2, @3) = i(@1 + W2 + W3)H3(@1, W2, 3) 
and 
Y(t) = ox | hy (ty) Wt —1))dr 
+ oe | | ho (T1, T2)W(t —T1) W(t —T2)dt1dt2 
+ oe | | | hg (71,72, 73) W(t —T1)W(t —T2) W(t —73)dt\dt2dT3, (12.138) 
where 
, 1 , : 
hy (11) = se | Hi (w) exp(iwt;)dw 
; 1 on 
hp (T,T2) = Ome | | H2(@ 1, @2) exp[i(w jt; + @2T2)|dw \dw> (12.139) 
h3(t,,72,73) = | | | H3(@ 1,2, @3) expli(w yt) + W2T2 + W373) ]dw dwrdws, 
(2x)? 
and H, are defined as 
367 
