fix mistakes

src/sage/algebras/letterplace/free_algebra_letterplace.pyx

@@ -3,7 +3,7 @@
 #       Copyright (C) 2011 Simon King <[email protected]>
 #  Distributed under the terms of the GNU General Public License (GPL),
 #  version 2 or any later version.  The full text of the GPL is available at:
-#                  http://www.gnu.org/licenses/
+#                  https://www.gnu.org/licenses/
 #
 ###############################################################################
 
@@ -185,7 +185,7 @@ cdef MPolynomialRing_libsingular make_letterplace_ring(base_ring, blocks):
     cdef i
     cdef tuple names0 = base_ring.variable_names()
     cdef list names = list(names0)
-    for i in range(blocks):
+    for i in range(1, blocks):
         T += T0
         names.extend([x + '_' + str(i) for x in names0])
     return PolynomialRing(base_ring.base_ring(), names, order=T,
@@ -340,7 +340,7 @@ cdef class FreeAlgebra_letterplace(Algebra):
         p = self._current_ring.gen(i)
         cdef int n
         cdef int j = self.__ngens - 1
-        for n in range(deg):
+        for n in range(1, deg):
             j += self.__ngens
             p *= self._current_ring.gen(j)
         return FreeAlgebraElement_letterplace(self, p)
@@ -689,7 +689,7 @@ cdef class FreeAlgebra_letterplace(Algebra):
         CG = CyclicPermutationGroup(C.ngens())
         for y in G:
             out.extend([y] + [y * CG[ngens * (n + 1)]
-                              for n in xrange(d - y.degree())])
+                              for n in range(d - y.degree())])
         return C.ideal(out)
 
     ###########################