diff --git a/src/sage/libs/pari/gen.pyx b/src/sage/libs/pari/gen.pyx
index 6179fc061d1..af9a35139ab 100644
--- a/src/sage/libs/pari/gen.pyx
+++ b/src/sage/libs/pari/gen.pyx
@@ -2254,14 +2254,7 @@ cdef class gen(sage.structure.element.RingElement):
             precision = P.get_series_precision()
         pari_catch_sig_on()
         cdef long vn = P.get_var(v)
-        if isexactzero(f.g):
-            # Special case for f = 0, because scalarser() is broken
-            # in PARI 2.5.5, causing e.g. Ser(gen_0) to give O(x^0).
-            # This is fixed in PARI 2.6.
-            if vn == -1:
-                vn = 0  # otherwise the variable will be called '#'
-            return P.new_gen(zeroser(vn, precision))
-        elif typ(f.g) == t_VEC:
+        if typ(f.g) == t_VEC:
             # The precision flag is ignored for vectors, so we first
             # convert the vector to a polynomial.
             return P.new_gen(gtoser(gtopolyrev(f.g, vn), vn, precision))
@@ -5268,7 +5261,7 @@ cdef class gen(sage.structure.element.RingElement):
     def phi(gen n):
         """
         Return the Euler phi function of n.
-        
+
         EXAMPLES::
 
             sage: pari(10).phi()
@@ -5429,10 +5422,10 @@ cdef class gen(sage.structure.element.RingElement):
 
         OUTPUT:
 
-        -  ``gen`` - a PARI ell structure.
+        -  ``gen`` -- a PARI ell structure.
 
         EXAMPLES:
-        
+
         An elliptic curve with integer coefficients::
 
             sage: e = pari([0,1,0,1,0]).ellinit(); e
@@ -5474,7 +5467,7 @@ cdef class gen(sage.structure.element.RingElement):
         - ``c`` - the product of the local Tamagawa numbers of `e`.
 
         - ``faN`` is the factorization of `N`
-        
+
         - ``L[i]`` is ``elllocalred(E, faN[i,1])``
 
         EXAMPLES::
@@ -5507,7 +5500,7 @@ cdef class gen(sage.structure.element.RingElement):
         OUTPUT: point on E
 
         EXAMPLES:
-        
+
         First we create an elliptic curve::
 
             sage: e = pari([0, 1, 1, -2, 0]).ellinit()
@@ -6382,7 +6375,9 @@ cdef class gen(sage.structure.element.RingElement):
         pari_catch_sig_on()
         return P.new_gen(ellsub(self.g, t0.g, t1.g))
 
-    def elltaniyama(self, long n=16):
+    def elltaniyama(self, long n=-1):
+        if n < 0:
+            n = P.get_series_precision()
         pari_catch_sig_on()
         return P.new_gen(elltaniyama(self.g, n))
 
@@ -6581,7 +6576,7 @@ cdef class gen(sage.structure.element.RingElement):
         REFERENCES:
 
         .. [PariUsers] User's Guide to PARI/GP,
-           http://pari.math.u-bordeaux.fr/pub/pari/manuals/2.5.1/users.pdf
+           http://pari.math.u-bordeaux.fr/pub/pari/manuals/2.7.0/users.pdf
         """
         pari_catch_sig_on()
         n = bnfcertify(self.g)
@@ -6953,7 +6948,7 @@ cdef class gen(sage.structure.element.RingElement):
         - ``fa``: If present, encodes a subset of primes at which to
           check for maximality. This must be one of the three following
           things:
-        
+
             - an integer: check all primes up to ``fa`` using trial
               division.
 
diff --git a/src/sage/rings/fast_arith.pyx b/src/sage/rings/fast_arith.pyx
index a2247756c05..954f19dd699 100644
--- a/src/sage/rings/fast_arith.pyx
+++ b/src/sage/rings/fast_arith.pyx
@@ -122,7 +122,7 @@ cpdef prime_range(start, stop=None, algorithm="pari_primes", bint py_ints=False)
         [2499923, 2499941, 2499943, 2499947, 2499949, 2499953, 2499967, 2499983, 2499989, 2499997]
 
     A non-trivial range without primes::
-    
+
         sage: prime_range(4652360, 4652400)
         []
 
diff --git a/src/sage/schemes/elliptic_curves/ell_rational_field.py b/src/sage/schemes/elliptic_curves/ell_rational_field.py
index 527076f65b3..4e1c2ed6415 100644
--- a/src/sage/schemes/elliptic_curves/ell_rational_field.py
+++ b/src/sage/schemes/elliptic_curves/ell_rational_field.py
@@ -600,7 +600,7 @@ def pari_curve(self, prec=None, factor=1):
 
             sage: Ep = EllipticCurve('903b3').pari_curve()
 
-        This still works, even When the curve coefficients are large
+        This still works, even when the curve coefficients are large
         (see :trac:`13163`)::
 
             sage: E = EllipticCurve([4382696457564794691603442338788106497, 28, 3992, 16777216, 298])
@@ -3708,7 +3708,7 @@ def torsion_points(self, algorithm="pari"):
 
         Some curves with large torsion groups::
 
-            sage: E = EllipticCurve([-1386747,368636886])
+            sage: E = EllipticCurve([-1386747, 368636886])
             sage: T = E.torsion_subgroup(); T
             Torsion Subgroup isomorphic to Z/2 + Z/8 associated to the Elliptic Curve defined by y^2  = x^3 - 1386747*x + 368636886 over Rational Field
             sage: T == E.torsion_subgroup(algorithm="doud")