c(ε)
(л +
-Vi/fi (⅛)
∑j . s-~r⅛ffj(<Ы
7~ιΛa + ∣e) 1[i+v(е)]’ vε
7 - 1 ∖ 1 - 7/
(38)
with V(ε) being defined in equation (20). The latter follows from f (e⅛)/-
V = fι(ɛie)/ — Vi — sι + sii ^i∙ This proves the first part of equation (21).
Now we we prove the second part of equation (21). Substitute f z(⅛) / f (⅛)
in equation (31) from (33) and multiply the equation by — (Λi + eiε/(1 - 7))∙
This yields
7 - 2 de-ι
7 - 1 dε
λ + '■ "/0 - 7) d⅛ = c(ε) (λ, + -ɪ
dei∣dε dε- у 1 - 7
∀ i, ε∙
(39)
The factor of d2ei/de2 equals the inverse first term in equation (36). Hence
it follows from equation (36) and (15) that this factor equals
fi (eis')
(40)
-V
Insert (40) in (39) and obtain after aggregation across investors since
∑i d2ei/de2 = 0,
7—2 + Σ -4τd2e√dε2 = c(ε) fA + γ-e^^ ( ∀ ε (41)
7- 1 t ^) V 1 - 7 J
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