3088 varieties: A solution to the Ackermann constant problem
John Slaney · Journal of Symbolic Logic · 1985
Abstract It is shown that there are exactly six normal DeMorgan monoids generated by the idntity element alone. The free DeMorgan monoid with no generators but the identity is characterised and shown to have exactly three thousand and eighty-eight elements. This result solves the “Ackermann constant problem” of describing the structure of sentential constants in the logic R.