A Sheffer-Criterion for Partial 4-Valued Logic
We determine the minimal covering of maximal partial clones in 4-valued logic. That means a necessary and sufficient condition for partial Sheffer functions in 4-valued logic in terms of the maximal partial clones is established. Furthermore several statements about members of the minimal covering of the maximal partial clones for any finite-valued logic are established.
Keywords: partial functions; partial Sheffer functions; maximal clones; minimal covering