### 5.2.2 Tests : ==, !=, >, >=, <, =<

==, !=, >, >=, <, =< are infixed operators.

a==b tests the equality between a and b and returns 1
if a is equal to b and 0 otherwise.

a!=b returns 1 if a and b are different and 0
otherwise.

a>=b returns 1 if a is greater than or equal to b
and 0 otherwise.

a>b returns 1 if a is strictly greater than b
and 0 otherwise.

a<=b returns 1 if a is less than or equal to b and
0 otherwise.

a<b returns 1 if a is strictly less than b
and 0 otherwise.

To write an algebraic function having the same result as an
if...then...else, we use the boolean function ifte.

For example :

f(x):=ifte(x>0,true,false)

defines the boolean function f such that f(x)= true if
x ∈ (0;+∞[ and f(x)=false if x ∈ (−∞;0].

Input :

f(0)==0

Output :

1

Look out !

a=b is not a boolean !!!!

a==b is a boolean.