Appendix
1.1 The Fossil Fuel Market
Throughout the appendix the commodity in period one is chosen as numeraire. Rearranging of (7)–(9), (20), and (21) yields:
$$\begin{aligned} p_{e1}-X^{E1}_{e_{F1}}-p_{x2}X^{E2}_{e_{F1}}&= 0, \end{aligned}$$
(39)
$$\begin{aligned} p_{e2}-p_{x2}X^{E2}_{e_{F2}}&= 0, \end{aligned}$$
(40)
$$\begin{aligned} e_{Ft}-\overline{e}_{At}-e_{Nt}&= 0,\quad t=1,2, \end{aligned}$$
(41)
$$\begin{aligned} X^{A1}_{\overline{e}_{A1}}-p_{e1}-\pi _1&= 0, \end{aligned}$$
(42)
$$\begin{aligned} p_{x2}X^{A2}_{\overline{e}_{A2}}-p_{e2}-\pi _2&= 0, \end{aligned}$$
(43)
$$\begin{aligned} X^{N1}_{e_{N1}}-p_{e1}&= 0, \end{aligned}$$
(44)
$$\begin{aligned} p_{x2}X^{N2}_{e_{N2}}-p_{e2}&= 0. \end{aligned}$$
(45)
Total differentiation of (39)–(45) yields:
$$\begin{aligned}&\displaystyle \mathrm{d}p_{e1}-X^{E1}_{e_{F1}e_{F1}}\mathrm{d}e_{F1}-X^{E2}_{e_{F1}}\mathrm{d}p_{x2} -p_{x2}\Bigg [X^{E2}_{e_{F1}e_{F1}}\mathrm{d}e_{F1}+X^{E2}_{e_{F1}e_{F2}}\mathrm{d}e_{F2}\Bigg ]=0,\end{aligned}$$
(46)
$$\begin{aligned}&\displaystyle \mathrm{d}p_{e2}-X^{E2}_{e_{F2}}\mathrm{d}p_{x2}-p_{x2}\Bigg [X^{E2}_{e_{F2}e_{F1}} \mathrm{d}e_{F1}+X^{E2}_{e_{F2}e_{F2}}\mathrm{d}e_{F2}\Bigg ]=0,\end{aligned}$$
(47)
$$\begin{aligned}&\displaystyle \mathrm{d}e_{Ft}-\mathrm{d}\overline{e}_{At}-\mathrm{d}e_{Nt}=0,\quad t=1,2,\end{aligned}$$
(48)
$$\begin{aligned}&\displaystyle X^{A1}_{\overline{e}_{A1}\overline{e}_{A1}}\mathrm{d}\overline{e}_{A1} -\mathrm{d}p_{e1}-\mathrm{d}\pi _1=0,\end{aligned}$$
(49)
$$\begin{aligned}&\displaystyle X^{A2}_{\overline{e}_{A2}}\mathrm{d}p_{x2}+p_{x2}X^{A2}_{\overline{e}_{A2} \overline{e}_{A2}}\mathrm{d}\overline{e}_{A2}-\mathrm{d}p_{e2}-\mathrm{d}\pi _2=0, \end{aligned}$$
(50)
$$\begin{aligned}&\displaystyle \frac{\widehat{e}_{N1}}{\widehat{p}_{e1}}-\eta _{N1}=0,\end{aligned}$$
(51)
$$\begin{aligned}&\displaystyle \frac{\widehat{e}_{N2}}{\widehat{p}_{e2}-\widehat{p}_{x2}}-\eta _{N2}=0, \end{aligned}$$
(52)
where \(\eta _{Nt}:=\frac{X^{Nt}_{e_{Nt}}}{e_{Nt}X^{Nt}_{e_{Nt} e_{Nt}}}<0\) for \(t=1,2\).
Inserting (51) and (52) in (48) and afterwards inserting in (46)–(47) yields:
$$\begin{aligned}&\mathrm{d}p_{e1}-X^{E1}_{e_{F1}e_{F1}}\Bigg [\mathrm{d}\overline{e}_{A1}+e_{N1} \eta _{N1}\widehat{p}_{e1}\Bigg ]-X^{E2}_{e_{F1}}\mathrm{d}p_{x2}-p_{x2} \Bigg [X^{E2}_{e_{F1}e_{F1}}\Bigg [\mathrm{d}\overline{e}_{A1}\nonumber \\&\left. \quad +\,e_{N1}\eta _{N1}\widehat{p}_{e1}\Bigg ]+X^{E2}_{e_{F1}e_{F2}}\Bigg [\mathrm{d}\overline{e}_{A2}+e_{N2}\eta _{N2}\left[ \widehat{p}_{e2}- \widehat{p}_{x2}\right] \Bigg ]\right] =0,\end{aligned}$$
(53)
$$\begin{aligned}&\mathrm{d}p_{e2}-X^{E2}_{e_{F2}}\mathrm{d}p_{x2}-p_{x2}\Bigg [X^{E2}_{e_{F2} e_{F1}}\Bigg [\mathrm{d}\overline{e}_{A1}+e_{N1}\eta _{N1}\widehat{p}_{e1}\Bigg ] \nonumber \\&\quad +\,X^{E2}_{e_{F2}e_{F2}}\Bigg [\mathrm{d}\overline{e}_{A2}+e_{N2}\eta _{N2}\left[ \widehat{p}_{e2}-\widehat{p}_{x2} \right] \Bigg ]\Bigg ]=0. \end{aligned}$$
(54)
Inserting (53) in (54) yields:
$$\begin{aligned} \mathrm{d}p_{e1}&= -\frac{\frac{p_{e1}}{e_{N1}\eta _{N1}}[\Gamma _0-p_{e1} [p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]]}{\Gamma _0}\mathrm{d}\overline{e}_{A1}\nonumber \\&+\,\,\frac{p_{e1}p_{e2}p_{x2}X^{E2}_{e_{F1}e_{F2}}}{\Gamma _0}\mathrm{d}\overline{e}_{A2}+\frac{p_{e1}X^{E2}_{e_{F1}}[p_{e2}-p_{x2}X^{E2}_{ e_{F2}e_{F2}}e_{N2}\eta _{N2}]}{\Gamma _0}\mathrm{d}p_{x2},\end{aligned}$$
(55)
$$\begin{aligned} \mathrm{d}p_{e2}&= \frac{p_{e1}p_{e2}p_{x2}X^{E2}_{e_{F2}e_{F1}}}{\Gamma _0} \mathrm{d}\overline{e}_{A1}\nonumber \\&-\,\,\frac{\frac{p_{e2}}{e_{N2}\eta _{N2}}[\Gamma _0-p_{e2}[p_{e1} -[X^{E1}_{e_{F1}e_{F1}}+p_{x2}X^{E2}_{e_{F1}e_{F1}}]e_{N1} \eta _{N1}]]}{\Gamma _0}\mathrm{d}\overline{e}_{A2}\nonumber \\&+\,\,\frac{X^{E2}_{e_{F2}} \Gamma _3}{\Gamma _0}\mathrm{d}p_{x2}, \end{aligned}$$
(56)
where \(\Gamma _0=[p_{e1}-[X^{E1}_{e_{F1}e_{F1}}+p_{x2} X^{E2}_{e_{F1}e_{F1}}]e_{N1}\eta _{N1}][p_{e2}-p_{x2} X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]-p_{x2}X^{E2}_{e_{F1} e_{F2}}e_{N1}\eta _{N1}\cdot p_{x2}X^{E2}_{e_{F2}e_{F1}} e_{N2}\eta _{N2}\) and \(\Gamma _3=\Gamma _0+\frac{p_{x2} X^{E2}_{e_{F1}}}{p_{e2}}\cdot p_{x2}X^{E2}_{e_{F2} e_{F1}}e_{N1}\eta _{N1}\cdot p_{e2}\).
Inserting (51) and (52) in (48) and afterwards inserting (55) and (56) yields:
$$\begin{aligned} \mathrm{d}e_{F1}&= \frac{p_{e1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2} \eta _{N2}]}{\Gamma _0}\mathrm{d}\overline{e}_{A1}+\frac{p_{e2}p_{x2} X^{E2}_{e_{F1}e_{F2}}e_{N1}\eta _{N1}}{\Gamma _0}\mathrm{d}\overline{e}_{A2} \nonumber \\&+\,\,\frac{X^{E2}_{e_{F1}}e_{N1}\eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2} e_{F2}}e_{N2}\eta _{N2}]}{\Gamma _0}\mathrm{d}p_{x2},\end{aligned}$$
(57)
$$\begin{aligned} \mathrm{d}e_{F2}&= \frac{p_{e1}p_{x2}X^{E2}_{e_{F2}e_{F1}}e_{N2}\eta _{N2}}{\Gamma _0}\mathrm{d}\overline{e}_{A1}+\frac{p_{e2}[p_{e1}-[X^{E1}_{e_{F1} e_{F1}}+p_{x2}X^{E2}_{e_{F1}e_{F1}}]e_{N1}\eta _{N1}]}{\Gamma _0}\mathrm{d}\overline{e}_{A2}\nonumber \\&+\,\,\frac{X^{E2}_{e_{F1}}e_{N1}\eta _{N1}[p_{x2}X^{E2}_{e_{F2}e_{F1}} e_{N2}\eta _{N2}]}{\Gamma _0}\mathrm{d}p_{x2}. \end{aligned}$$
(58)
Adding (57)–(58) yields:
$$\begin{aligned} \mathrm{d}e_{F1}+\mathrm{d}e_{F2}=\mathrm{d}e_{F\varSigma }=\frac{p_{e1}\Gamma _1}{\Gamma _0}\mathrm{d}\overline{e}_{A1}+\frac{p_{e2}\Gamma _2}{\Gamma _0}\mathrm{d}\overline{e}_{A2}+\frac{X^{E2}_{e_{F1}}e_{N1}\eta _{N1}\Gamma _1}{\Gamma _0}\mathrm{d}p_{x2}, \end{aligned}$$
(59)
where \(\Gamma _1=p_{e2}+[p_{x2}X^{E2}_{e_{F2}e_{F1}}-p_{x2} X^{E2}_{e_{F2}e_{F2}}]e_{N2}\eta _{N2}\) and \(\Gamma _2=p_{e1} -[X^{E1}_{e_{F1}e_{F1}}+p_{x2}X^{E2}_{e_{F1}e_{F1}}-p_{x2} X^{E2}_{e_{F1}e_{F2}}]e_{N1}\eta _{N1}\).
1.2 The Commodity Market
The relative commodity demand of \(A,N,F \text{ and } E\) is equal to:
$$\begin{aligned} q^d=\frac{\sum x_{i1}}{\sum x_{i2}}=\frac{x_{A1}+x_{N1}+x_{F1} +X^{E1}}{x_{A2}+x_{N2}+x_{F2}+X^{E2}},\quad i=A,N,F,E. \end{aligned}$$
(60)
Inserting (22) and (27) in (60) yields:
$$\begin{aligned} q^d=\left( \frac{\alpha _1p_{x2}}{\alpha _2}\right) ^\sigma -\left( \frac{\alpha _1p_{x2}}{\alpha _2}\right) ^\sigma \frac{X^{E2}}{X^{A2}+X^{N2}}+\frac{X^{E1}}{X^{A2}+X^{N2}}. \end{aligned}$$
(61)
Total differentiation of (61) and afterwards inserting (39)–(45) and (27) yields:
$$\begin{aligned} \mathrm{d}{q}^d&= \left( \frac{\alpha _1p_{x2}}{\alpha _2}\right) ^\sigma \sigma \widehat{p}_{x2}-\left( \frac{\alpha _1p_{x2}}{\alpha _2}\right) ^\sigma \sigma \widehat{p}_{x2}\frac{X^{E2}}{X^{A2}+X^{N2}}\nonumber \\&-\left( \frac{\alpha _1p_{x2}}{\alpha _2}\right) ^\sigma \frac{\mathrm{d}X^{E2}(X^{A2}+X^{N2})-X^{E2}(\mathrm{d}X^{A2}+\mathrm{d}X^{N2})}{(X^{A2} +X^{N2})^2}\nonumber \\&+\,\,\frac{\mathrm{d}X^{E1}(X^{A2}+X^{N2})-X^{E1}(\mathrm{d}X^{A2}+\mathrm{d}X^{N2})}{(X^{A2}+X^{N2})^2}\nonumber \\&= \frac{x^s_{A1}+x^s_{N1}-x_{E1}}{x^s_{A2}+x^s_{N2}}\sigma \widehat{p}_{x2}-\frac{\frac{\pi _2}{p_{x2}}\left( \frac{x^s_{A1} +x^s_{N1}}{x^s_{A2}+x^s_{N2}}-\frac{x^s_{A1}+x^s_{N1}-x_{E1}}{x^s_{A2} +x^s_{N2}-x_{E2}}\right) }{x^s_{A2}+x^s_{N2}}\mathrm{d}{\overline{e}}_{A2} \nonumber \\&+\,\,\frac{X^{E1}_{e_{F1}}-X^{E2}_{e_{F1}}\cdot \frac{x^s_{A1}+x^s_{N1} -x_{E1}}{x^s_{A2}+x^s_{N2}-x_{E2}}}{x^s_{A2}+x^s_{N2}}\mathrm{d}{e}_{F1} -\frac{X^{E2}_{e_{F2}}\cdot \frac{x^s_{A1}+x^s_{N1}}{x^s_{A2} +x^s_{N2}}}{x^s_{A2}+x^s_{N2}}\mathrm{d}{e}_{F2}. \end{aligned}$$
(62)
The relative commodity supply of \(A \text{ and } N\) is equal to:
$$\begin{aligned} q^s=\frac{\sum x^s_{j1}}{\sum x^s_{j2}}=\frac{X^{A1}+X^{N1}}{X^{A2}+X^{N2}},\quad j=A,N. \end{aligned}$$
(63)
Total differentiation of (63) and afterwards inserting (39)–(45) yields:
$$\begin{aligned}&\!\!\!\mathrm{d}{q}^s=\frac{(X^{A1}_{\overline{e}_{A1}}\mathrm{d}{\overline{e}}_{A1} +X^{N1}_{e_{N1}}\mathrm{d}{e}_{N1})(X^{A2}+X^{N2})-(X^{A1}+X^{N1}) (X^{A2}_{\overline{e}_{A2}}\mathrm{d}{\overline{e}}_{A2}+X^{N2}_{e_{N2}} \mathrm{d}{e}_{N2})}{(X^{A2}+X^{N2})^2}\nonumber \\&\,=\frac{\pi _1}{x^s_{A2}+x^s_{N2}}\mathrm{d}{\overline{e}}_{A1}{-} \frac{\frac{\pi _2}{p_{x2}}\cdot \frac{x^s_{A1}{+}x^s_{N1}}{x^s_{A2} +x^s_{N2}}}{x^s_{A2}+x^s_{N2}}\mathrm{d}{\overline{e}}_{A2}+\,\frac{X^{E1}_{e_{F1}}+p_{x2}X^{E2}_{e_{F1}}}{x^s_{A2}+x^s_{N2}} \mathrm{d}{e}_{F1}{-}\frac{X^{E2}_{e_{F2}}\cdot \frac{x^s_{A1}{+}x^s_{N1}}{x^s_{A2}+x^s_{N2}}}{x^s_{A2}+x^s_{N2}}\mathrm{d}{e}_{F2}.\nonumber \\ \end{aligned}$$
(64)
Equating (62) and (64) yields:
$$\begin{aligned} \mathrm{d}{p}_{x2}=\frac{p_{x2}}{\sigma }\left( \frac{\pi _1}{x^s_{A1} +x^s_{N1}-x_{E1}}\mathrm{d}{\overline{e}}_{A1}-\frac{\pi _2}{p_{x2} (x^s_{A2}+x^s_{N2}-x_{E2})}\mathrm{d}{\overline{e}}_{A2}+\Theta \mathrm{d}{e}_{F1}\right) , \end{aligned}$$
(65)
where \(\Theta =\frac{p_{x2}X^{E2}_{e_{F1}}}{x^s_{A1}+x^s_{N1}-x_{E1}} +\frac{p_{x2}X^{E2}_{e_{F1}}}{p_{x2}(x^s_{A2}+x^s_{N2}-x_{E2})}\).
1.3 The Combined Market
1.3.1 The Quantities on the Combined Market
Inserting (65) in (57) for \(\mathrm{d}{\overline{e}}_{A2}=0\) yields:
$$\begin{aligned} \mathrm{d}{e}_{F1}&= \frac{p_{e1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2} \eta _{N2}]}{\Gamma _0}\mathrm{d}\overline{e}_{A1}+\frac{X^{E2}_{e_{F1}}e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}{\Gamma _0}\nonumber \\&\cdot \frac{p_{x2}}{\sigma }\left( \frac{\pi _1}{x^s_{A1}+x^s_{N1} -x_{E1}}\mathrm{d}\overline{e}_{A1}+\Theta \mathrm{d}{e}_{F1}\right) \nonumber \\&= \frac{[p_{e1}\sigma +p_{x2}X^{E2}_{e_{F1}}\frac{\pi _1e_{N1}\eta _{N1}}{x^s_{A1}+x^s_{N1}-x_{E1}}][p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2} \eta _{N2}]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]} \mathrm{d}\overline{e}_{A1}. \end{aligned}$$
(66)
Inserting (65) and (66) in (58) for \(\mathrm{d}{\overline{e}}_{A2}=0\) yields:
$$\begin{aligned} \mathrm{d}{e}_{F2}&= \frac{p_{e1}p_{x2}X^{E2}_{e_{F2}e_{F1}}e_{N2} \eta _{N2}}{\Gamma _0}\mathrm{d}\overline{e}_{A1}+\frac{X^{E2}_{e_{F1}} e_{N1}\eta _{N1}[p_{x2}X^{E2}_{e_{F2}e_{F1}}e_{N2}\eta _{N2}]}{\Gamma _0} \nonumber \\&\cdot \frac{p_{x2}}{\sigma }\left( \frac{\pi _1}{x^s_{A1}+x^s_{N1} -x_{E1}}\mathrm{d}\overline{e}_{A1}\right. \nonumber \\&\left. \quad \quad \quad +\,\,\Theta \frac{[p_{e1}\sigma +p_{x2}X^{E2}_{e_{F1}} \frac{\pi _1e_{N1}\eta _{N1}}{x^s_{A1}+x^s_{N1}-x_{E1}}] [p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}[p_{e2} -p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\mathrm{d}\overline{e}_{A1} \right) \nonumber \\&= \frac{[p_{e1}\sigma +p_{x2}X^{E2}_{e_{F1}}\frac{\pi _1e_{N1} \eta _{N1}}{x^s_{A1}+x^s_{N1}-x_{E1}}]p_{x2}X^{E2}_{e_{F2}e_{F1}} e_{N2}\eta _{N2}}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]} \mathrm{d}\overline{e}_{A1}. \end{aligned}$$
(67)
Adding (66) and (67) yields:
$$\begin{aligned} \mathrm{d}{e}_{F1}+\mathrm{d}{e}_{F2}=\mathrm{d}{e}_{F\varSigma }=\frac{[p_{e1}\sigma \!\!+\!\!p_{x2}X^{E2}_{e_{F1}}\frac{\pi _1e_{N1}\eta _{N1}}{x^s_{A1}\!+\!x^s_{N1} \!-\!x_{E1}}]\Gamma _1}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}[p_{e2}\!-\!p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]} \mathrm{d}\overline{e}_{A1}.\qquad \end{aligned}$$
(68)
Inserting (66) and (68) in (29) yields:
$$\begin{aligned}&\mathrm{d}D(e_{F1},e_{F\varSigma })\gtreqless 0\nonumber \\&\Leftrightarrow \quad \Bigg [p_{e1}\sigma +p_{x2}X^{E2}_{e_{F1}} \frac{\pi _1e_{N1}\eta _{N1}}{x^s_{A1}\!+\!x^s_{N1}-x_{E1}}\Bigg ]\Bigg [[p_{e2} -p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]+\lambda \Gamma _1\Bigg ] \mathrm{d}\overline{e}_{A1}\gtreqless 0.\nonumber \\ \end{aligned}$$
(69)
Inserting (65) in (57) for \(\mathrm{d}{\overline{e}}_{A1}=0\) yields:
$$\begin{aligned} \mathrm{d}{e}_{F1}&= \frac{p_{e2}p_{x2}X^{E2}_{e_{F1}e_{F2}}e_{N1} \eta _{N1}}{\Gamma _0}\mathrm{d}\overline{e}_{A2}+\frac{X^{E2}_{e_{F1}} e_{N1}\eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}{\Gamma _0}\nonumber \\&\cdot \frac{p_{x2}}{\sigma }\left( -\frac{\pi _2}{p_{x2}(x^s_{A2} +x^s_{N2}-x_{E2})}\mathrm{d}\overline{e}_{A2}+\Theta \mathrm{d}e_{F1}\right) \nonumber \\&= \frac{p_{e2}\sigma p_{x2}X^{E2}_{e_{F1}e_{F2}}e_{N1}\eta _{N1}}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}[p_{e2} -p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\mathrm{d}\overline{e}_{A2} \nonumber \\&-\frac{p_{x2}X^{E2}_{e_{F1}}\frac{\pi _2e_{N1}\eta _{N1}}{p_{x2} (x^s_{A2}+x^s_{N2}-x_{E2})}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}} e_{N2}\eta _{N2}]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\mathrm{d}\overline{e}_{A2}. \end{aligned}$$
(70)
Inserting (65) and (70) in (58) for \(\mathrm{d}{\overline{e}}_{A1}=0\) yields:
$$\begin{aligned} \mathrm{d}{e}_{F2}&= \frac{p_{e2}[p_{e1}-[X^{E1}_{e_{F1}e_{F1}}+p_{x2} X^{E2}_{e_{F1}e_{F1}}]e_{N1}\eta _{N1}]}{\Gamma _0}\mathrm{d}\overline{e}_{A2} \nonumber \\&+\,\,\frac{X^{E2}_{e_{F1}}e_{N1}\eta _{N1}[p_{x2}X^{E2}_{e_{F2}e_{F1}} e_{N2}\eta _{N2}]}{\Gamma _0}\cdot \frac{p_{x2}}{\sigma }\left( -\frac{\pi _2}{p_{x2}(x^s_{A2}+x^s_{N2}-x_{E2})}\mathrm{d}\overline{e}_{A2} \right. \nonumber \\&+\,\,\Theta \frac{p_{e2}\sigma p_{x2}X^{E2}_{e_{F1}e_{F2}}e_{N1}\eta _{N1}}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}[p_{e2} -p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\mathrm{d}\overline{e}_{A2} \nonumber \\&\left. -\,\,\Theta \frac{p_{x2}X^{E2}_{e_{F1}}\frac{\pi _2e_{N1}\eta _{N1}}{p_{x2}(x^s_{A2}+x^s_{N2}-x_{E2})}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}} e_{N2}\eta _{N2}]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\mathrm{d}\overline{e}_{A2}\right) \nonumber \\&= \frac{p_{e2}\sigma [p_{e1}-[X^{E1}_{e_{F1}e_{F1}}+p_{x2}X^{E2}_{e_{F1} e_{F1}}]e_{N1}\eta _{N1}]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}} \Theta e_{N1}\eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2} \eta _{N2}]}\mathrm{d}\overline{e}_{A2}\nonumber \\&-\frac{p_{x2}X^{E2}_{e_{F1}}\frac{\pi _2e_{N1}\eta _{N1}}{p_{x2} (x^s_{A2}+x^s_{N2}-x_{E2})}p_{x2}X^{E2}_{e_{F2}e_{F1}}e_{N2}\eta _{N2} +p_{e2}p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}}{\sigma \Gamma _0 -p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}[p_{e2}-p_{x2} X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\mathrm{d}\overline{e}_{A2}.\nonumber \\ \end{aligned}$$
(71)
Adding (70) and (71) yields:
$$\begin{aligned} \mathrm{d}{e}_{F1}\!{+}\!\mathrm{d}{e}_{F2}\!=\!\mathrm{d}{e}_{F\varSigma }\!=\!\frac{p_{e2}\sigma \Gamma _2{-}p_{x2}X^{E2}_{e_{F1}}\frac{\pi _2e_{N1}\eta _{N1}}{p_{x2} (x^s_{A2}\!+\!x^s_{N2}\!-\!x_{E2})}\Gamma _1\!-\!p_{e2}p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}}{\sigma \Gamma _0\!-\!p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}[p_{e2}\!-\!p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2} \eta _{N2}]}\mathrm{d}\overline{e}_{A2}.\nonumber \\ \end{aligned}$$
(72)
Inserting (70) and (72) in (29) yields:
$$\begin{aligned}&\mathrm{d}D(e_{F1},e_{F\varSigma })\gtreqless 0\nonumber \\&\quad \Leftrightarrow \quad \Bigg [p_{e2}\sigma [p_{x2}X^{E2}_{e_{F1}e_{F2}} e_{N1}\eta _{N1}+\lambda \Gamma _2]-p_{x2}X^{E2}_{e_{F1}}\frac{\pi _2 e_{N1}\eta _{N1}}{p_{x2}(x^s_{A2}+x^s_{N2}-x_{E2})}\nonumber \\&\qquad \qquad \cdot [[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}] +\lambda \Gamma _1]-\lambda p_{e2}p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}\Bigg ]\mathrm{d}\overline{e}_{A2}\gtreqless 0.\nonumber \\ \end{aligned}$$
(73)
1.3.2 The Prices on the Combined Market
Inserting (66) in (65) for \(\mathrm{d}{\overline{e}}_{A2}=0\) yields:
$$\begin{aligned} \frac{\mathrm{d}{p}_{x2}}{\mathrm{d}{\overline{e}}_{A1}}&= \frac{p_{x2}}{\sigma } \left( \frac{\pi _1}{x^s_{A1}+x^s_{N1}-x_{E1}}\right. \nonumber \\&\left. +\,\,\Theta \frac{[p_{e1}\sigma +p_{x2}X^{E2}_{e_{F1}} \frac{\pi _1e_{N1}\eta _{N1}}{x^s_{A1}+x^s_{N1}-x_{E1}}][p_{e2} -p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}{\sigma \Gamma _0 -p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}[p_{e2}-p_{x2} X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\right) \nonumber \\&= \frac{p_{x2}\frac{\pi _1}{x^s_{A1}+x^s_{N1}-x_{E1}}\Gamma _0 +p_{e1}p_{x2}\Theta [p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2} \eta _{N2}]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]} \nonumber \\&> 0. \end{aligned}$$
(74)
Inserting (70) in (65) for \(\mathrm{d}{\overline{e}}_{A1}=0\) yields:
$$\begin{aligned} \frac{\mathrm{d}{p}_{x2}}{\mathrm{d}{\overline{e}}_{A2}}&= \frac{p_{x2}}{\sigma } \left( -\frac{\pi _2}{p_{x2}(x^s_{A2}+x^s_{N2}-x_{E2})}\right. \nonumber \\&\left. +\,\,\Theta \frac{p_{e2}\sigma p_{x2}X^{E2}_{e_{F1}e_{F2}}e_{N1} \eta _{N1}-p_{x2}X^{E2}_{e_{F1}}\frac{\pi _2e_{N1}\eta _{N1}}{p_{x2} (x^s_{A2}+x^s_{N2}-x_{E2})}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2} \eta _{N2}]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1} [p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\right) \nonumber \\&= -\frac{p_{x2}\frac{\pi _2}{p_{x2}(x^s_{A2}+x^s_{N2}-x_{E2})} \Gamma _0-p_{e2}p_{x2}\Theta p_{x2}X^{E2}_{e_{F1}e_{F2}}e_{N1} \eta _{N1}}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\nonumber \\&< 0. \end{aligned}$$
(75)
Inserting (74) in (55) for \(\mathrm{d}{\overline{e}}_{A2}=0\) yields:
$$\begin{aligned} \frac{\mathrm{d}{p}_{e1}}{\mathrm{d}{\overline{e}}_{A1}}&= -\frac{\frac{p_{e1}}{e_{N1}\eta _{N1}}[\Gamma _0-p_{e1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}} e_{N2}\eta _{N2}]]}{\Gamma _0}\nonumber \\&\quad +\,\,\frac{p_{e1}X^{E2}_{e_{F1}}[p_{e2}-p_{x2} X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}{\Gamma _0}\nonumber \\&\cdot \frac{p_{x2}\frac{\pi _1}{x^s_{A1}+x^s_{N1}-x_{E1}}\Gamma _0 +p_{e1}p_{x2}\Theta [p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2} \eta _{N2}]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\nonumber \\&= -\,\,\frac{\frac{p_{e1}}{e_{N1}\eta _{N1}}\sigma [\Gamma _0-p_{e1} [p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}[p_{e2} -p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\nonumber \\&+\,\,\frac{p_{e1}p_{x2}X^{E2}_{e_{F1}}[\frac{\pi _1}{x^s_{A1}+x^s_{N1} -x_{E1}}+\Theta ][p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}[p_{e2} -p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\nonumber \\&> 0. \end{aligned}$$
(76)
Inserting (74) in (56) for \(\mathrm{d}{\overline{e}}_{A2}=0\) yields:
$$\begin{aligned} \frac{\mathrm{d}{p}_{e2}}{\mathrm{d}{\overline{e}}_{A1}}&= \frac{p_{e1}p_{e2} p_{x2}X^{E2}_{e_{F2}e_{F1}}}{\Gamma _0}+\frac{X^{E2}_{e_{F2}}\Gamma _3}{\Gamma _0}\nonumber \\&\cdot \frac{p_{x2}\frac{\pi _1}{x^s_{A1}+x^s_{N1}-x_{E1}}\Gamma _0 +p_{e1}p_{x2}\Theta [p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2} \eta _{N2}]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\nonumber \\&= \frac{p_{e1}p_{e2}\sigma p_{x2}X^{E2}_{e_{F2}e_{F1}}+p_{x2} X^{E2}_{e_{F2}}\frac{\pi _1}{x^s_{A1}+x^s_{N1}-x_{E1}}\Gamma _3 +p_{e1}p_{x2}X^{E2}_{e_{F2}}\Theta [p_{e2}-p_{x2}X^{E2}_{e_{F2} e_{F2}}e_{N2}\eta _{N2}]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}} \Theta e_{N1}\eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2} \eta _{N2}]}\nonumber \\&> 0\Leftarrow \Gamma _3>0. \end{aligned}$$
(77)
Inserting (75) in (55) for \(\mathrm{d}{\overline{e}}_{A1}=0\) yields:
$$\begin{aligned} \frac{\mathrm{d}{p}_{e1}}{\mathrm{d}{\overline{e}}_{A2}}&= \frac{p_{e1}p_{e2} p_{x2}X^{E2}_{e_{F1}e_{F2}}}{\Gamma _0}+\frac{p_{e1}X^{E2}_{e_{F1}} [p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}{\Gamma _0}\nonumber \\&\cdot -\,\frac{p_{x2}\frac{\pi _2}{p_{x2}(x^s_{A2}+x^s_{N2}-x_{E2})} \Gamma _0-p_{e2}p_{x2}\Theta p_{x2}X^{E2}_{e_{F1}e_{F2}}e_{N1} \eta _{N1}}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}\nonumber \\&= \frac{p_{e1}p_{e2}\sigma p_{x2}X^{E2}_{e_{F1}e_{F2}}-p_{e1}p_{x2} X^{E2}_{e_{F1}}\frac{\pi _2}{p_{x2}(x^s_{A2}+x^s_{N2}-x_{E2})}[p_{e2} -p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]}{\sigma \Gamma _0-p_{x2} X^{E2}_{e_{F1}}\Theta e_{N1}\eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2} e_{F2}}e_{N2}\eta _{N2}]}\nonumber \\&= \frac{p_{e1}}{e_{N1}\eta _{N1}}\cdot \frac{\mathrm{d}{e}_{F1}}{\mathrm{d}{\overline{e}}_{A2}}\gtreqless 0\Leftrightarrow \frac{\mathrm{d}{e}_{F1}}{\mathrm{d}{\overline{e}}_{A2}}\lesseqgtr 0. \end{aligned}$$
(78)
Inserting (75) in (56) for \(\mathrm{d}{\overline{e}}_{A1}=0\) yields:
$$\begin{aligned} \frac{\mathrm{d}{p}_{e2}}{\mathrm{d}{\overline{e}}_{A2}}&= -\,\,\frac{\frac{p_{e2}}{e_{N2}\eta _{N2}}[\Gamma _0-p_{e2}[p_{e1}-[X^{E1}_{e_{F1}e_{F1}} +p_{x2}X^{E2}_{e_{F1}e_{F1}}]e_{N1}\eta _{N1}]]}{\Gamma _0} +\frac{X^{E2}_{e_{F2}}\Gamma _3}{\Gamma _0}\nonumber \\&\cdot -\frac{p_{x2}\frac{\pi _2}{p_{x2}(x^s_{A2}+x^s_{N2}-x_{E2})} \Gamma _0-p_{e2}p_{x2}\Theta p_{x2}X^{E2}_{e_{F1}e_{F2}}e_{N1} \eta _{N1}}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]} \nonumber \\&= -\frac{\frac{p_{e2}}{e_{N2}\eta _{N2}}\sigma [\Gamma _0-p_{e2} [p_{e1}-[X^{E1}_{e_{F1}e_{F1}}+p_{x2}X^{E2}_{e_{F1}e_{F1}}]e_{N1} \eta _{N1}]]}{\sigma \Gamma _0-p_{x2}X^{E2}_{e_{F1}}\Theta e_{N1} \eta _{N1}[p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}]} \nonumber \\&\!-\!\frac{p_{x2}X^{E2}_{e_{F2}}\frac{\pi _2}{p_{x2}(x^s_{A2}+x^s_{N2} \!-\!x_{E2})}\Gamma _3{-}p_{e2}p_{x2}\Theta p_{x2}e_{N1}\eta _{N1} [X^{E2}_{e_{F2}}X^{E2}_{e_{F1}e_{F2}}\!-\!X^{E2}_{e_{F1}} X^{E2}_{e_{F2}e_{F2}}]}{\sigma \Gamma _0\!{-}\!p_{x2}X^{E2}_{e_{F1}} \Theta e_{N1}\eta _{N1}[p_{e2}\!-\!p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2} \eta _{N2}]}.\nonumber \\ \end{aligned}$$
(79)
1.4 The Gammas
$$\begin{aligned} \Gamma _0&= \Bigg [p_{e1}-\Bigg [X^{E1}_{e_{F1}e_{F1}}+p_{x2}X^{E2}_{e_{F1}e_{F1}}\Bigg ] e_{N1}\eta _{N1}\Bigg ]\Bigg [p_{e2}-p_{x2}X^{E2}_{e_{F2}e_{F2}}e_{N2}\eta _{N2}\Bigg ] \nonumber \\&-p_{x2}X^{E2}_{e_{F1}e_{F2}}e_{N1}\eta _{N1}\cdot p_{x2}X^{E2}_{e_{F2} e_{F1}}e_{N2}\eta _{N2}\nonumber \\&= \frac{p_{e2}e_{N2}\left| \eta _{N2}\right| p_{e1}e_{N1}\left| \eta _{N1}\right| }{e_{F1}\eta _{F1,2}e_{F2}\eta _{F2,1}}\cdot \left[ \left( \frac{e_{F1} \eta _{F1,2}}{e_{N2}\left| \eta _{N2}\right| }+\frac{e_{F1}\eta _{F1,2}}{e_{F2} \eta _{F2,2}}\right) \right. \\&\quad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \left. \cdot \left( \frac{e_{F2}\eta _{F2,1}}{e_{N1} \left| \eta _{N1}\right| }+\frac{e_{F2}\eta _{F2,1}}{e_{F1}\eta _{F1,1}} \right) -1\right] ,\end{aligned}$$
(80)
$$\begin{aligned} \Gamma _1&= p_{e2}+\Bigg [p_{x2}X^{E2}_{e_{F2}e_{F1}}-p_{x2}X^{E2}_{e_{F2} e_{F2}}\Bigg ]e_{N2}\eta _{N2}\nonumber \\&= \frac{p_{e2}e_{N2}\left| \eta _{N2}\right| }{e_{F1}\eta _{F1,2}}\cdot \left( \frac{e_{F1}\eta _{F1,2}}{e_{N2}\left| \eta _{N2}\right| }+\frac{e_{F1} \eta _{F1,2}}{e_{F2}\eta _{F2,2}}-1\right) ,\nonumber \\&\gtreqless 0\quad \Leftrightarrow \quad \frac{e_{F1}\eta _{F1,2}}{e_{N2} \left| \eta _{N2}\right| }+\frac{e_{F1}\eta _{F1,2}}{e_{F2}\eta _{F2,2}} \gtreqless 1,\end{aligned}$$
(81)
$$\begin{aligned} \Gamma _2&= p_{e1}-\Bigg [X^{E1}_{e_{F1}e_{F1}}+p_{x2}X^{E2}_{e_{F1}e_{F1}} -p_{x2}X^{E2}_{e_{F1}e_{F2}}\Bigg ]e_{N1}\eta _{N1}\nonumber \\&= \frac{p_{e1}e_{N1}\left| \eta _{N1}\right| }{e_{F2}\eta _{F2,1}}\cdot \left( \frac{e_{F2}\eta _{F2,1}}{e_{N1}\left| \eta _{N1}\right| }+\frac{e_{F2} \eta _{F2,1}}{e_{F1}\eta _{F1,1}}-1\right) ,\\&\gtreqless 0\quad \Leftrightarrow \quad \frac{e_{F2}\eta _{F2,1}}{e_{N1} \left| \eta _{N1}\right| }+\frac{e_{F2}\eta _{F2,1}}{e_{F1}\eta _{F1,1}} \gtreqless 1,\end{aligned}$$
(82)
$$\begin{aligned} \Gamma _3&= \Gamma _0+\frac{p_{x2}X^{E2}_{e_{F1}}}{p_{e2}}\cdot p_{x2}X^{E2}_{e_{F2}e_{F1}}e_{N1}\eta _{N1}\cdot p_{e2} \nonumber \\&= \frac{p_{e2}e_{N2}\left| \eta _{N2}\right| p_{e1}e_{N1}\left| \eta _{N1}\right| }{e_{F1}\eta _{F1,2}e_{F2}\eta _{F2,1}}\cdot \left[ \left( \frac{e_{F1} \eta _{F1,2}}{e_{N2}\left| \eta _{N2}\right| }+\frac{e_{F1}\eta _{F1,2}}{e_{F2} \eta _{F2,2}}\right) \right. \nonumber \\&\qquad \qquad \qquad \qquad \qquad \qquad \qquad \left. \cdot \left( \frac{e_{F2}\eta _{F2,1}}{e_{N1} \left| \eta _{N1}\right| }+\frac{e_{F2}\eta _{F2,1}}{e_{F1}\eta _{F1,1}} \!\right) -1\!-\!\frac{p_{x2}X^{E2}_{e_{F1}}}{p_{e1}}\cdot \frac{e_{F2} \eta _{F2,1}}{e_{N2}\left| \eta _{N2}\right| }\!\right] \!,\nonumber \\&> \underline{\Gamma _3}=p_{x2}X^{E2}_{e_{F1}}[p_{x2}X^{E2}_{e_{F2}} +p_{x2}X^{E2}_{e_{F2}e_{F1}}e_{N1}\eta _{N1}]\nonumber \\&= p_{x2}X^{E2}_{e_{F1}}\cdot p_{x2}X^{E2}_{e_{F2}e_{F1}}e_{N1} \left| \eta _{N1}\right| \left( \frac{e_{F1}\left| \eta _{F1,2}\right| }{e_{N1} \left| \eta _{N1}\right| }-1\right) ,\nonumber \\&\gtreqless 0\quad \Leftrightarrow \quad \frac{e_{F1}\eta _{F1,2}}{e_{N1} \left| \eta _{N1}\right| }\gtreqless 1, \end{aligned}$$
(83)
where \({\underline{\Gamma }_3}\) is a lower limit for \(\Gamma _3\).