Appendix A
Proof of Lemma 1. , s.t., , we can obtain by making .
(i) If ,
, we can obtain by making ;
(a) When
,
;
The first order conditions satisfy and . The second order conditions satisfy , and . So the Hessian matrix is , is jointly concave in and if .
We set up the Lagrangian function as follows:
The critical points of
are the solutions to
The first-order conditions satisfy and . The second-order conditions satisfy , , and . So the Hessian matrix is , is jointly concave in and if . The optimal solutions of are the solutions of , namely, , .
This gives us three series of critical points: , , , , , ; or , , , , , ; or , , , , , .
The first solution exists when , the second solution exists when , and the third solution exists when and .
(b) If , , ;
(c) If , , ;
(ii) If , , ;
(iii) If , , .
Therefore, we compare (i), (ii) and (iii), and we obtain that there exists the unique optimal solution as follows:
(a) when , , , , , , ; , , , ;
(b) when , , , , , , ; , , , ;
(c) when and ,
, ,
, ,
, ,
, ,
,
. □
We can further obtain the optimal decisions as Lemma 1 shows by integrating the above solutions.
Proof of Proposition 1. In the region of and , i.e., , where is derived through , is derived through , retailer 2 always discloses information. Considering retailer 2’s information disclosure, retailer 1 will disclose information if , i.e., , where is derived through ; if , retailer 1 will disclose information. Therefore, we obtain that when , two retailers will reach equilibrium; when , two retailers will reach equilibrium.
If and , i.e., , retailer 2 always withholds information. Retailer 1 will disclose information if , namely, where is derived from . If , retailer 1 will disclose information. Therefore, if , two retailers will reach equilibrium; if , they will reach equilibrium.
If and , i.e., , retailer 2 will adopt the same information strategy as retailer 1’s strategy in equilibrium. Retailer 1 discloses information if , namely, , where is derived by , retailer 1 will withhold information if . Therefore, if , two retailers will reach equilibrium; if , two retailers will reach equilibrium.
If
and
, i.e.,
, retailer 2 will adopt the opposite information strategy as retailer 1’s strategy in equilibrium. Retailer 1 discloses information if
, namely,
, where
is derived by
, retailer 1 will withhold information if
. Therefore, if
, two retailers will reach
equilibrium; if
, two retailers will reach
equilibrium. Therefore, we can obtain the final information strategies as
Table A1 shows.
Table A1.
Two retailers’ information disclosure policies.
Table A1.
Two retailers’ information disclosure policies.
| Conditions | Information Strategies |
|---|
| or | |
| or | |
| or | |
| or | |
(1) When ,
, ,
, ,
, ,
, .
is derived from , is derived from , is derived from , is derived from , is derived from , is derived from .
, we let , ; if , we obtain ; else, if , we obtain .
, , if , we obtain ; else, if , we obtain .
, , , , , , . We let , , , ; if or , ; if , .
, , since , we can obtain , thus, we obtain .
(2) When ,
, ;
, ;
, ;
, .
is derived from ;
is derived from ;
is derived from ;
is derived from ;
is derived from .
since
and .
(3) When ,
, ;
, ;
, ;
, .
is derived from ;
is derived from ;
is derived from ;
is derived from ;
is derived from ;
;
;
;
since ,
,
,
,
;
, we can obtain .
.
(4) When ,
, ,
, ,
, ,
is derived from ;
is derived from ;
is derived from ;
is derived from ;
is derived from .
, since , , ; ; , we can obtain .
, since , , , , ; we can obtain .
, , since , we can obtain , then, we obtain .
, , , , if , else, . , , , . If , there exists making , if , else, . if .
. . □
Proof of Proposition 2. when ,
(1) when ,
if , ;
if , ;
if , ;
if , ;
if , ;
(2) when , . □
Proof of Proposition 4. (1) , , , , , ;
, , , , , ; thus, we can obtain that there exists , if ; else, .
, .
(2) , ,
, , , , , ; there exist , if ; else, .
, , , , , ; .
(3) , , , , , , , ; there exist , if ; else, .
, , , . , ; .
(4) ,
, , .
(5) ,
,
, . Since , we can obtain
, , , , , ; there exist , if ; else, .
, , , ,
, ; .
, , , ; , , therefore, we can obtain and
, , , ; if , then, .
, , , ; . □
Proof of Proposition 5. (1)
Table 8 shows that the formation of strategy
in equilibrium should satisfy
,
,
due to the fact that ,
, if , we can obtain ;
(2) , if , we can obtain ;
(3) ,
,
,
,
,
, . □
Proof of Proposition 6. (1) For ease of analysis, we let .
, ,
,
,
,
;
, ,
,
,
,
.
(2) , ,
, ,
, ,
;
, ,
,
,
,
. □