For any theory system
$T$
$\frac{d\rho}{dt}=K\rho^{x}t^{y}\rho^{z}_{pub}$
the long-term mean Publication Multiplier of
$T$
$\rho \rightarrow \infty$
$e^{\frac{z(y+1)}{1-x}}$
$\frac{d\rho}{dt}=K\rho^{x}t^{y}\rho^{z}_{pub}$
This is a separable differential equation, after some rearrangement we have:
$\rho^{-x}d\rho = Kt^{y}\rho^{z}_{pub}dt$
Integrate both sides,
$\int\rho^{-x}d\rho = \int Kt^{y}\rho^{z}_{pub}dt$
Since
$K\rho^{z}_{pub}$
$\int\rho^{-x}d\rho = K\rho^{z}_{pub}\int t^{y}dt$
Evaluate both Integrals,
$\frac{\rho^{1-x}}{1-x} = \frac{K\rho^{z}_{pub}}{y+1}t^{y+1} + C$
In an Endgame situation,
$t \rightarrow \infty$
$C$
$\frac{\rho^{1-x}}{1-x} = K’\rho^{z}_{pub}t^{y+1}$
We solve the equation to get:
$\rho = \left[K’(1-x)\rho^{z}_{pub}t^{y+1}\right]^{\frac{1}{1-x}}\qquad (3-3)$
The goal of ours is to find the Publication Multiplier that gives the maximum speed measured in a \logarithmic scale, which can be expressed with the equation below:
$Speed ∝ \frac{\ln(\rho) - \ln(\rho_{pub})}{t}\qquad (3-4)$
We substitute (3-3) into (3-4) and get:
$\frac{\ln(\rho) - \ln(\rho_{pub})}{t} = \frac{\ln\left[K’(1-x)\rho^{z}{pub}t^{y+1}\right]^{\frac{1}{1-x}} - \ln(\rho)}{t}$
$ = \frac{\frac{\ln\left[K’(1-x)\right]+\ln\left(\rho^{z}{pub}\right)+\ln\left(t^{y+1}\right)}{1-x} - \ln(\rho)}{t}\qquad (3-5)$
In the Endgame,
$\ln\left[K’(1-x)\right]$
$\frac{\frac{\ln\left[K’(1-x)\right]+\ln\left(\rho^{z}{pub}\right)+\ln\left(t^{y+1}\right)}{1-x} - \ln(\rho)}{t} \simeq \frac{\frac{\ln\left(\rho^{z}{pub}\right)+\ln\left(t^{y+1}\right)}{1-x} - \ln(\rho)}{t}$
$ = \frac{\left(\frac{z}{1-x} - 1\right)\ln\rho_{pub} + \frac{y+1}{1-x}\ln( t )}{t}$
$ = \frac{x+z-1}{1-x}\ln\rho_{pub}\cdot\frac{1}{t} + \frac{y+1}{1-x}\cdot\frac{\ln( t )}{t}\qquad (3-6)$
We use differentiation to find the maximum of the expression above:
$\frac{d}{dt}\left(\frac{x+z-1}{1-x}\ln\rho_{pub}\cdot\frac{1}{t} + \frac{y+1}{1-x}\cdot\frac{\ln( t )}{t}\right) = 0$
$\frac{x+z-1}{1-x}\ln\rho_{pub}\cdot\frac{d}{dt}\frac{1}{t} + \frac{y+1}{1-x}\cdot\frac{d}{dt}\frac{\ln( t )}{t} = 0$
$\frac{x+z-1}{1-x}\ln\rho_{pub}\cdot\left(-\frac{1}{t^2}\right) + \frac{y+1}{1-x}\cdot\frac{d}{dt}\frac{\frac{1}{t}\cdot t-\ln( t )}{t^2} = 0$
$\frac{y+1}{1-x}\cdot\frac{1-\ln( t )}{t^2} = \frac{x+z-1}{1-x}\ln\rho_{pub}\frac{1}{t^2}$
Since
$t>0, x \neq 1$
$(y+1)[1-\ln(t)] = (x+z-1)\ln\rho_{pub}$
Thus,
$\ln( t ) = 1-\frac{x+z-1}{y+1}\ln\rho_{pub}\qquad (3-7)$
The publication multiplier of the theory is:
$r = \left(\frac{\rho}{\rho_{pub}}\right)^z$
Since
$r>0$
$\ln( r ) = z\left[\ln(\rho)-\ln(\rho_{pub})\right]$
$\ln( r ) = zt\left(\frac{x+z-1}{1-x}\ln\rho_{pub}\cdot\frac{1}{t} + \frac{y+1}{1-x}\cdot\frac{\ln( t )}{t}\right)$
$= z\left(\frac{x+z-1}{1-x}\ln\rho_{pub} + \frac{y+1}{1-x}\ln(t)\right)\qquad (3-8)$
Substitute (3-7) into (3-8),
$\ln®=$
$z\left[\frac{x+z-1}{1-x}\ln\rho_{pub}+\frac{y+1}{1-x}\left(1-\frac{x+z-1}{y+1}\ln\rho_{pub}\right)\right]$
$ = z\left[\frac{(x+z-1)\ln\rho_{pub} + (y+1)(1-\frac{x+z-1}{y+1}\ln\rho_{pub})}{1-x}\right]$
$ = z\left[\frac{(x+z-1)\ln\rho_{pub} + (y+1) - (x+z-1)\ln\rho_{pub}}{1-x}\right]$
$ = \frac{z(y+1)}{1-x}\qquad (3-9)$
From (3-9), we get:
$r = e^{\frac{z(y+1)}{1-x}}$
Q.E.D.