\newcommand{\d}[1]{\widehat{\delta}_{#1}}
\newcommand{\g}[1]{\widehat{\gamma}_{#1}}
\newcommand{\a}[1]{\widehat{\alpha}_{#1}}
\newcommand{\B}[1]{\beta_{#1}}
\newcommand{\b}[1]{\widehat{\beta}_{#1}}

\newcommand{\B0}{{\beta_0}}
\newcommand{\B1}{{\beta_1}}
\newcommand{\B2}{{\beta_2}}
\newcommand{\B3}{{\beta_3}}

\newcommand{\b0}{\widehat{\beta}_0}
\newcommand{\b1}{\widehat{\beta}_1}
\newcommand{\b2}{\widehat{\beta}_2}
\newcommand{\b3}{\widehat{\beta}_3}
\newcommand{\b4}{\widehat{\beta}_4}

\newcommand{\d0}{\widehat{\delta}_0}
\newcommand{\d1}{\widehat{\delta}_1}
\newcommand{\d2}{\widehat{\delta}_2}
\newcommand{\d3}{\widehat{\delta}_3}


\newcommand{\g0}{\widehat{\gamma}_0}
\newcommand{\g1}{\widehat{\gamma}_1}
\newcommand{\g2}{\widehat{\gamma}_2}
\newcommand{\g3}{\widehat{\gamma}_3}