Understanding Machine Learning: From Theory to Algorithms

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19.6 Exercises 267

W.l.o.g. assume thatp≤ 1 /2. Now use Lemma 19.7 to show that

y P
1 ,...,yj
y∼Pp[hS(x)^6 =y]≤

(

1 +


8

k

)

y∼Pp[^1 [p>^1 /2]^6 =y].


  • Show that


yP∼p[^1 [p>^1 /2]^6 =y] =p= min{p,^1 −p}≤min{η(x),^1 −η(x)}+|p−η(x)|.


  • Combine all the preceding to obtain that the second summand in Equa-
    tion (19.3) is bounded by
    (
    1 +



8

k

)

LD(h?) + 3c


d.


  • User= (2/)dto obtain that:


E

S

[LD(hS)]≤

(

1 +


8

k

)

LD(h?) + 3c


d+2(2/)

dk
m

.

Set= 2m−^1 /(d+1)and use

6 cm−^1 /(d+1)


d+

2 k
e

m−^1 /(d+1)≤

(

6 c


d+k

)

m−^1 /(d+1)

to conclude the proof.
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