### 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.