User:Mathieu/Test

$(-E)*\ldots*(-F)\;==\; E*\ldots*F$ (if an even number of -)

$(-E)*\ldots*(-F)\;==\; -\,(E*\ldots*F)$ (if an odd number of -)

$\frac{\ }{\textbf{H},\textbf{P} \;\;\vdash \;\; \textbf{P}}$

$\frac{X}{\textbf{H},\textbf{P} \;\;\vdash \;\; \textbf{P}}$

HYP

$\frac{}{\textbf{H},\textbf{P} \;\;\vdash \;\; \textbf{P}}$

HYP