diff --git a/pymath/abstract_polynom.py b/pymath/abstract_polynom.py
index 3a68782..969fcf9 100644
--- a/pymath/abstract_polynom.py
+++ b/pymath/abstract_polynom.py
@@ -57,6 +57,14 @@ class AbstractPolynom(Explicable):
         'Q'
         """
         super(AbstractPolynom, self).__init__()
+
+        try:
+            # Remove 0 at the end of the coefs
+            while coefs[-1] == 0:
+                coefs = coefs[:-1]
+        except IndexError:
+            pass
+
         self.feed_coef(coefs)
         self._letter = letter
         self.name = name
diff --git a/pymath/polynom.py b/pymath/polynom.py
index bc99854..247d476 100644
--- a/pymath/polynom.py
+++ b/pymath/polynom.py
@@ -8,8 +8,25 @@ from .generic import isNumerand
 from .random_expression import RdExpression
 from .abstract_polynom import AbstractPolynom
 
+from functools import wraps
+import inspect
+
 __all__ = ["Polynom"]
 
+def polynom_factory(func):
+    """ Decorator which specify the type of polynom that the function returns """
+    @wraps(func)
+    def wrapper(*args, **kwrds):
+        P = func(*args, **kwrds)
+        if isinstance(P,Polynom) and P.degree == 2:
+            from .polynomDeg2 import Polynom_deg2
+            new_P = Polynom_deg2(poly=P)
+            new_P.steps = P.steps
+            return new_P
+        else:
+            return P
+    return wrapper
+
 class Polynom(AbstractPolynom):
 
     """Polynom view as a function.
@@ -139,6 +156,15 @@ class Polynom(AbstractPolynom):
         ans.name = self.name + "'"
         return ans
 
+# Decorate methods which may return Polynoms
+methods_list = ["__add__", "__call__", "__mul__", "__neg__", "__pow__",
+        "__radd__", "__rmul__", "__rsub__", "__sub__", "derivate", 
+        "reduce", "simplify", "random"]
+for name, func in inspect.getmembers(Polynom):
+    if name in methods_list:
+        setattr(Polynom, name, polynom_factory(func))
+
+
 def test(p,q):
     print("---------------------")
     print("---------------------")
diff --git a/pymath/polynomDeg2.py b/pymath/polynomDeg2.py
index b1e1a31..de88570 100644
--- a/pymath/polynomDeg2.py
+++ b/pymath/polynomDeg2.py
@@ -35,7 +35,12 @@ class Polynom_deg2(Polynom):
         # Création du polynom
         return Polynom_deg2(coefs = coefs, letter = letter, name = name)
 
-    def __init__(self, coefs = [0, 0, 1], letter = "x", name = "P"):
+    def __init__(self, coefs = [0, 0, 1], letter = "x", name = "P", poly = 0):
+        if poly:
+            coefs = poly._coef
+            letter = poly._letter
+            name = poly.name
+
         if len(coefs) < 3 or len(coefs) > 4:
             raise ValueError("Polynom_deg2 have to be degree 2 polynoms, they need 3 coefficients, {} are given".format(len(coefs)))
         if coefs[2] == 0: