6.1 Truth tables

The meaning of conjunction, disjunction, negation and implication can be defined by truth tables. Since there are definitions, there is no need to ask why they are like this.

Table 1: Truth table of conjunction.

$X$	$Y$	$X \wedge Y$
T	T	T
T	F	F
F	T	F
F	F	F

Table 2: Truth table of disjunction.

$X$	$Y$	$X \vee Y$
T	T	T
T	F	T
F	T	T
F	F	F

Table 3: Truth table of implication.

$X$	$Y$	$X \rightarrow Y$
T	T	T
T	F	F
F	T	T
F	F	T

Table 4: Truth table of negation.

$X$	$\neg X$
T	F
F	T