In particular, di > c" => ¾(c<) ≤ <7l(cz∕), as claimed in the proposition. By
<7,(∙) monotonously decreasing, it follows also that dqi(di)∕dc,i exists almost
everywhere (a.e.), cf. LafFont and Tirole(1993) p. 63.
Rewriting (2), we get that for all di and d- with di > d-
-(ξ - <)⅛(<) < SiW - SiW) + < ■ ¾(<) - ⅛ ∙ QiW ≤-Wi - <)¾(ξ)
or equivalently
<⅞(¾(4) - QiW)} < ⅝(cj) - ¾(<⅜') < <(¾(g,.) - ¾(⅛))
Cj - ɑi' ^^ Ci - cj' - di - c"
We see therefore that since ⅛(czl)∕dczl exists (a.e.), so does dsɪ(eɔ/dej. Fur-
thermore, going to the limit (di → eɔ in (2), we get that
d(¾(ci)-<⅞∙¾(cj))
-----J------- -QiW ≤ θ «•
This shows that the less efficient types earn less profit and it implies
fc? _ _
4^ ɑi ʧi(ɛi) d* J Qi[Ci) dci
which is the last property in the proposition.
We shall now show that the two properties in Proposition 1 implies in-
centive compatibility. Inserting the expression for ¾(.) into the incentive
compatibility constraint (1) we get
A⅛ + ci ∙ ςi(ci) + / qi(ci) d⅛ - ci ■ qi(ci) >
Γci _
ki + ⅛∙qi(di) + J qi(ci) dci - ci ∙ qi(c,i) ∀i,ci,c'.
Reducing and rewriting, we get
∕,c<z ∕*< __ Γci
/ qdci)dci> / ρi(c')dci+ / qi(ci)dci Vi,ci,di
Jci Jci Jcti
which holds because qi{.) is weakly decreasing. ■
According to Proposition 1, the less efficient types produce less. Also,
the expected payment is - up to an integration constant - determined en-
tirely from the production scheme. Proposition 1 makes it easy to analyze
alternative organizations as we shall see below.