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STOCHASTIC

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JAMES A. OHLSON<br />

A number of interesting cases satisfy the last corollary. When U(W) is<br />

negative exponential (-exp{-cW}, c>0), then U l3 \W) is bounded for all<br />

W^ 0 and EU (3 \(p{W)){W-\f = o{t). Also, if U(W) = (c + Wf/y, y0, then supvg0|C/ (3) ((p)! = j(y — 2)(-y — 1)|c v ~ 3 and the corollary is satisfied.<br />

The case when U(W) = W'/y, or log W, requires more care, and condition<br />

(ii) remains in force. However, condition (i) is satisfied for any fixed e > 0;<br />

thus, it is easily verified that supv£E| t/( 0 as ? -• 0. A slight reparametrization<br />

of E\t~ 1 Q3\ produces an expression for which the probability measure<br />

is independent of t. The restated convergence problem is now one of convergence<br />

in mean, and necessary and sufficient conditions are well known in<br />

measure theory. 5 For purposes of the present paper, this result is not in a<br />

particularly useful form, and there is no reason to restate these conditions here.<br />

5 See, for example, Halmos [2, p. 108].<br />

228 PART III STATIC PORTFOLIO SELECTION MODELS

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