\documentclass[12pt]{article}
\usepackage{amsmath,amssymb,amsfonts}
\begin{document}
We have calculated the equation of state of protoneutron star
matter by using the lowest order constrained variational method.
In our calculations, the modern Argonne potential $(AV_{18})$
together with its older model potential $(AV_{14})$ are used. It
is found that the equation of state for high lepton fraction is
stiffer than for low lepton fraction. It is seen that the
increasing effect of pressure due to high lepton fraction and due
to entropy are comparable. It is shown that the temperature and
adiabatic index depend on the values of both entropy and lepton
fraction.
\end{document}