Material nonimplication
Material nonimplication or abjunction (Latin ab = "from", junctio =–"joining") is the negation of material implication. That is to say that for any two propositions and , the material nonimplication from to is true if and only if the negation of the material implication from to is true. This is more naturally stated as that the material nonimplication from to is true only if is true and is false.
It may be written using logical notation as , , or "Lpq" (in Bocheński notation), and is logically equivalent to , and .
Definition
Truth table
T  T  F 
T  F  T 
F  T  F 
F  F  F 
Logical Equivalences
Material nonimplication may be defined as the negation of material implication.

In classical logic, it is also equivalent to the negation of the disjunction of and , and also the conjunction of and
Properties
falsehoodpreserving: The interpretation under which all variables are assigned a truth value of "false" produces a truth value of "false" as a result of material nonimplication.
Symbol
The symbol for material nonimplication is simply a crossedout material implication symbol. Its Unicode symbol is 8603 (decimal).
Natural language
Rhetorical
"p but not q."
Computer science
Bitwise operation: A&(~B)
Logical operation: A&&(!B)
See also
References