user_operator takes as argument :
user_operator returns 1 if the definition is done and else returns 0.
Example 1
Let R be defined on ℝ by x R y= x*y+x+y.
To define the law R, input :
Output :
Input :
Do not forget to put spaces around R.
Output :
Example 2
Let S be defined on ℕ by :
for x and y integers, x S y <=> x and y are not coprime.
To define the law S, input :
Output :
Input :
Do not forget to put spaces around S.
Output :
Input :
Do not forget to put spaces around S.
Output :