Logical Connectives (Binary)
I – Conjunction
Informally: “and”
Symbols: 
• &&
A B
These
are called conjuncts.
The meaning of conjunction is
expressed by this truth table:
|
A |
B |
A |
|
T |
T |
T |
|
T |
F |
F |
|
F |
T |
F |
|
F |
F |
F |
A conjunction is true if and
only if both conjuncts are true.
II – Disjunction
Informally: “or”
Symbols: 
||
A B
These
are called disjuncts.
The meaning of disjunction is
expressed by this truth table:
|
A |
B |
A |
|
T |
T |
T |
|
T |
F |
T |
|
F |
T |
T |
|
F |
F |
F |
A disjunction is true if
either (or both) disjunct(s) are true.
III – Implication (Conditional)
Informally:
“if – then”
Symbols: 
A B
antecedent
consequence
|
A |
B |
A |
|
T |
T |
T |
|
T |
F |
F |
|
F |
T |
T |
|
F |
F |
T |
An implication is false only
if the antecedent is true and the consequence is false.
IV – Equivalence (Biconditional)
Informally:
“if and only if” “iff”
Symbol
This connective is actually
short hand for: (A B) (B A)
|
A |
B |
A |
|
T |
T |
T |
|
T |
F |
F |
|
F |
T |
F |
|
F |
F |
T |
Equivalence is true only if
both sides are true or both sides are false.
Logical Connectives (Unary)
