\newcommand{\sbullet}{%
  \texorpdfstring{\textsbullet}{\textbullet}%
}
\DeclareRobustCommand{\textsbullet}{%
  \unskip~\,\begin{picture}(1,1)(0,-3)\circle*{3}\end{picture}\ %
}
\usepackage{newunicodechar}
\newunicodechar{⊥}{\ensuremath{\bot}}
\newunicodechar{⊤}{\ensuremath{\top}}
\newunicodechar{∨}{\ensuremath{\vee}}
\newunicodechar{∧}{\ensuremath{\wedge}}
\newunicodechar{⇒}{\ensuremath{\Rightarrow}}
\newunicodechar{•}{\ensuremath{\sbullet}}
\newunicodechar{λ}{\ensuremath{\lambda}}
\newunicodechar{Λ}{\ensuremath{\Lambda}}
\newunicodechar{∎}{\ensuremath{\blacksquare}}
\newunicodechar{μ}{\ensuremath{\mu}}
\newunicodechar{ℕ}{\ensuremath{\mathbb{N}}}
\newunicodechar{✓}{\ensuremath{\checkmark}}