Fix Symbol creation

diff --git a/pypol/linear.py b/pypol/linear.py
index bd7037b..8f73fd3 100644 (file)
--- a/pypol/linear.py
+++ b/pypol/linear.py
@@ -62,7 +62,7 @@ class Expression:
                 for symbol, coefficient in coefficients if coefficient != 0]
         if len(coefficients) == 0:
             return Constant(constant)
                 for symbol, coefficient in coefficients if coefficient != 0]
         if len(coefficients) == 0:
             return Constant(constant)

-        elif len(coefficients) == 1:
+        elif len(coefficients) == 1 and constant == 0:

             symbol, coefficient = coefficients[0]
             if coefficient == 1:
                 return Symbol(symbol)
             symbol, coefficient = coefficients[0]
             if coefficient == 1:
                 return Symbol(symbol)