diff --git a/polymani.pl b/polymani.pl
index faa596c..c0bd94f 100644
--- a/polymani.pl
+++ b/polymani.pl
@@ -351,7 +351,6 @@ term_to_list(-P, [-P2]) :-
 %% Tests:
 %% ?- term_to_list(1, X).
 %@ X = [1] .
-%@ X = [1] .
 %% ?- term_to_list(-1, X).
 %@ X = [-1] .
 %% ?- term_to_list(x, X).
@@ -368,7 +367,6 @@ term_to_list(-P, [-P2]) :-
 %@ X = -1 .
 %% ?- term_to_list(X, [x^1, -1]).
 %@ X = -1*x .
-%@ X = -1*x .
 %% ?- term_to_list(X, [-x^1]).
 %@ X = -x .
 %% ?- term_to_list(X, [y^1, x^1]).
@@ -379,6 +377,8 @@ term_to_list(-P, [-P2]) :-
 %@ X = x^4*z^2*y^6 .
 %% ?- term_to_list(X, [y^6, z^2, x^4, -2]).
 %@ X = -2*x^4*z^2*y^6 .
+%% ?- term_to_list(X, [x^1, 0]).
+%@ X = 0*x .
 
 %% simplify_term(+Term_In:term, ?Term_Out:term) is det
 %
@@ -526,7 +526,7 @@ simplify_polynomial(P, P2) :-
 %
 %  Simplifies a polynomial represented as a list.
 %
-simplify_polynomial_as_list(L, L11) :-
+simplify_polynomial_as_list(L, L13) :-
     %% Convert each term to a list
     maplist(term_to_list, L, L2),
     %% Sort each sublist; done so the next
@@ -540,23 +540,31 @@ simplify_polynomial_as_list(L, L11) :-
     %% Done so the next call simplifies has less work
     maplist(sort(0, @=<), L5, L6),
     join_similar_terms(L6, L7),
+    %% Exclude any sublist that includes a 0 (such as the
+    %% equivalent to the term 0*x)
+    exclude(member(0), L7, L8),
     %% Reverse each sublist, because the next call
     %% reverses the result
-    maplist(reverse, L7, L8),
-    maplist(term_to_list, L9, L8),
+    maplist(reverse, L8, L9),
+    maplist(term_to_list, L10, L9),
     %% Delete any 0 from the list
-    delete(L9, 0, L10),
+    delete(L10, 0, L11),
     %% Sort list converting back gives the result in the correct order
-    sort(0, @=<, L10, L11).
+    sort(0, @=<, L11, L12),
+    (
+	%% If the list is empty, the result is a list with 0
+	L12 = [], L13 = [0]
+    ;
+        %% Otherwise, this is the result
+        L13 = L12
+    ).
 %% Tests:
 %% ?- simplify_polynomial_as_list([x, 1, x^2, x*y, 3*x^2, 4*x], L).
 %@ L = [1, 4*x^2, 5*x, x*y] .
-%@ L = [1, 4*x^2, 5*x, x*y] .
 %% ?- simplify_polynomial_as_list([1, x^2, x*y, 3*x^2, -4, -1*x], L).
 %@ L = [-3, -1*x, 4*x^2, x*y] .
-%@ L = [-3, -1*x, 4*x^2, x*y] .
-%% ?- simplify_polynomial_as_list([0*x], L).
-%@ L = [0*x] .
+%% ?- simplify_polynomial_as_list([0*x, 0], L).
+%@ L = [0] .
 
 %% join_similar_terms(+P:ListList, -P2:ListList) is det
 %