Modal Logic
From Wiki Notes @ WuJiewen.com, by Jiewen Wu
Syntax
The basic modal logic is defined using a set of propositional letters <math>\,\Phi</math>, and a unary operator <math>\,\Box</math>. A well-formed formula is then given by the rule
<math>\phi := p\mid\neg\phi\mid\phi\wedge\phi\mid\Box\phi</math>
