#==
const all = '∀'
const exist = '∃'
const dot = '.'
const lpar = '('
const rpar = ')'
const land = '∧'
const lor  = '∨'
const imp  = '⇒'
const eqv  = '≡'
const neg  = '¬'


const fpos = :+
const fneg = :-
const fall = :all
const fexist = :exist
const fimp = :imply
const feqv = :equiv
const and  = :and
const or   = :or
==#
