An empty clause is a clause defined from an empty set of literals. It is variously denoted 
, 
, or 
.
The truth evaluation of an empty disjunctive clause is FALSE, whereas the truth evaluation of an empty conjunctive clause is TRUE.
Empty Clause
See also
ClauseExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Empty Clause." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/EmptyClause.html