diff --git a/include/boost/numeric/interval/arith.hpp b/include/boost/numeric/interval/arith.hpp
index d2284c8..7028c4c 100644
--- a/include/boost/numeric/interval/arith.hpp
+++ b/include/boost/numeric/interval/arith.hpp
@@ -187,39 +187,39 @@ interval<T, Policies> operator*(const interval<T, Policies>& x,
   const T& yl = y.lower();
   const T& yu = y.upper();
 
-  if (interval_lib::detail::is_neg(xl))
-    if (interval_lib::detail::is_pos(xu))
-      if (interval_lib::detail::is_neg(yl))
-        if (interval_lib::detail::is_pos(yu)) // M * M
+  if (interval_lib::user::is_neg(xl))
+    if (interval_lib::user::is_pos(xu))
+      if (interval_lib::user::is_neg(yl))
+        if (interval_lib::user::is_pos(yu)) // M * M
           return I(min(rnd.mul_down(xl, yu), rnd.mul_down(xu, yl)),
                    max(rnd.mul_up  (xl, yl), rnd.mul_up  (xu, yu)), true);
         else                    // M * N
           return I(rnd.mul_down(xu, yl), rnd.mul_up(xl, yl), true);
       else
-        if (interval_lib::detail::is_pos(yu)) // M * P
+        if (interval_lib::user::is_pos(yu)) // M * P
           return I(rnd.mul_down(xl, yu), rnd.mul_up(xu, yu), true);
         else                    // M * Z
           return I(static_cast<T>(0), static_cast<T>(0), true);
     else
-      if (interval_lib::detail::is_neg(yl))
-        if (interval_lib::detail::is_pos(yu)) // N * M
+      if (interval_lib::user::is_neg(yl))
+        if (interval_lib::user::is_pos(yu)) // N * M
           return I(rnd.mul_down(xl, yu), rnd.mul_up(xl, yl), true);
         else                    // N * N
           return I(rnd.mul_down(xu, yu), rnd.mul_up(xl, yl), true);
       else
-        if (interval_lib::detail::is_pos(yu)) // N * P
+        if (interval_lib::user::is_pos(yu)) // N * P
           return I(rnd.mul_down(xl, yu), rnd.mul_up(xu, yl), true);
         else                    // N * Z
           return I(static_cast<T>(0), static_cast<T>(0), true);
   else
-    if (interval_lib::detail::is_pos(xu))
-      if (interval_lib::detail::is_neg(yl))
-        if (interval_lib::detail::is_pos(yu)) // P * M
+    if (interval_lib::user::is_pos(xu))
+      if (interval_lib::user::is_neg(yl))
+        if (interval_lib::user::is_pos(yu)) // P * M
           return I(rnd.mul_down(xu, yl), rnd.mul_up(xu, yu), true);
         else                    // P * N
           return I(rnd.mul_down(xu, yl), rnd.mul_up(xl, yu), true);
       else
-        if (interval_lib::detail::is_pos(yu)) // P * P
+        if (interval_lib::user::is_pos(yu)) // P * P
           return I(rnd.mul_down(xl, yl), rnd.mul_up(xu, yu), true);
         else                    // P * Z
           return I(static_cast<T>(0), static_cast<T>(0), true);
@@ -237,9 +237,9 @@ interval<T, Policies> operator*(const T& x, const interval<T, Policies>& y)
   const T& yl = y.lower();
   const T& yu = y.upper();
   // x is supposed not to be infinite
-  if (interval_lib::detail::is_neg(x))
+  if (interval_lib::user::is_neg(x))
     return I(rnd.mul_down(x, yu), rnd.mul_up(x, yl), true);
-  else if (interval_lib::detail::is_zero(x))
+  else if (interval_lib::user::is_zero(x))
     return I(static_cast<T>(0), static_cast<T>(0), true);
   else
     return I(rnd.mul_down(x, yl), rnd.mul_up(x, yu), true);
@@ -256,13 +256,13 @@ interval<T, Policies> operator/(const interval<T, Policies>& x,
   if (interval_lib::detail::test_input(x, y))
     return interval<T, Policies>::empty();
   if (in_zero(y))
-    if (!interval_lib::detail::is_zero(y.lower()))
-      if (!interval_lib::detail::is_zero(y.upper()))
+    if (!interval_lib::user::is_zero(y.lower()))
+      if (!interval_lib::user::is_zero(y.upper()))
         return interval_lib::detail::div_zero(x);
       else
         return interval_lib::detail::div_negative(x, y.lower());
     else
-      if (!interval_lib::detail::is_zero(y.upper()))
+      if (!interval_lib::user::is_zero(y.upper()))
         return interval_lib::detail::div_positive(x, y.upper());
       else
         return interval<T, Policies>::empty();
@@ -276,13 +276,13 @@ interval<T, Policies> operator/(const T& x, const interval<T, Policies>& y)
   if (interval_lib::detail::test_input(x, y))
     return interval<T, Policies>::empty();
   if (in_zero(y))
-    if (!interval_lib::detail::is_zero(y.lower()))
-      if (!interval_lib::detail::is_zero(y.upper()))
+    if (!interval_lib::user::is_zero(y.lower()))
+      if (!interval_lib::user::is_zero(y.upper()))
         return interval_lib::detail::div_zero<T, Policies>(x);
       else
         return interval_lib::detail::div_negative<T, Policies>(x, y.lower());
     else
-      if (!interval_lib::detail::is_zero(y.upper()))
+      if (!interval_lib::user::is_zero(y.upper()))
         return interval_lib::detail::div_positive<T, Policies>(x, y.upper());
       else
         return interval<T, Policies>::empty();
@@ -293,12 +293,12 @@ interval<T, Policies> operator/(const T& x, const interval<T, Policies>& y)
 template<class T, class Policies> inline
 interval<T, Policies> operator/(const interval<T, Policies>& x, const T& y)
 {
-  if (interval_lib::detail::test_input(x, y) || interval_lib::detail::is_zero(y))
+  if (interval_lib::detail::test_input(x, y) || interval_lib::user::is_zero(y))
     return interval<T, Policies>::empty();
   typename Policies::rounding rnd;
   const T& xl = x.lower();
   const T& xu = x.upper();
-  if (interval_lib::detail::is_neg(y))
+  if (interval_lib::user::is_neg(y))
     return interval<T, Policies>(rnd.div_down(xu, y), rnd.div_up(xl, y), true);
   else
     return interval<T, Policies>(rnd.div_down(xl, y), rnd.div_up(xu, y), true);
diff --git a/include/boost/numeric/interval/arith2.hpp b/include/boost/numeric/interval/arith2.hpp
index 3486095..7b1632b 100644
--- a/include/boost/numeric/interval/arith2.hpp
+++ b/include/boost/numeric/interval/arith2.hpp
@@ -36,7 +36,7 @@ interval<T, Policies> fmod(const interval<T, Policies>& x,
     return interval<T, Policies>::empty();
   typename Policies::rounding rnd;
   typedef typename interval_lib::unprotect<interval<T, Policies> >::type I;
-  const T& yb = interval_lib::detail::is_neg(x.lower()) ? y.lower() : y.upper();
+  T const &yb = interval_lib::user::is_neg(x.lower()) ? y.lower() : y.upper();
   T n = rnd.int_down(rnd.div_down(x.lower(), yb));
   return (const I&)x - n * (const I&)y;
 }
@@ -59,7 +59,7 @@ interval<T, Policies> fmod(const T& x, const interval<T, Policies>& y)
     return interval<T, Policies>::empty();
   typename Policies::rounding rnd;
   typedef typename interval_lib::unprotect<interval<T, Policies> >::type I;
-  const T& yb = interval_lib::detail::is_neg(x) ? y.lower() : y.upper();
+  T const &yb = interval_lib::user::is_neg(x) ? y.lower() : y.upper();
   T n = rnd.int_down(rnd.div_down(x, yb));
   return x - n * (const I&)y;
 }
@@ -75,13 +75,13 @@ interval<T, Policies> division_part1(const interval<T, Policies>& x,
   if (detail::test_input(x, y))
     return I::empty();
   if (in_zero(y))
-    if (!detail::is_zero(y.lower()))
-      if (!detail::is_zero(y.upper()))
+    if (!user::is_zero(y.lower()))
+      if (!user::is_zero(y.upper()))
         return detail::div_zero_part1(x, y, b);
       else
         return detail::div_negative(x, y.lower());
     else
-      if (!detail::is_zero(y.upper()))
+      if (!user::is_zero(y.upper()))
         return detail::div_positive(x, y.upper());
       else
         return I::empty();
@@ -107,13 +107,13 @@ interval<T, Policies> multiplicative_inverse(const interval<T, Policies>& x)
   typename Policies::rounding rnd;
   if (in_zero(x)) {
     typedef typename Policies::checking checking;
-    if (!detail::is_zero(x.lower()))
-      if (!detail::is_zero(x.upper()))
+    if (!user::is_zero(x.lower()))
+      if (!user::is_zero(x.upper()))
         return I::whole();
       else
         return I(-checking::inf(), rnd.div_up(one, x.lower()), true);
     else
-      if (!detail::is_zero(x.upper()))
+      if (!user::is_zero(x.upper()))
         return I(rnd.div_down(one, x.upper()), checking::inf(), true);
       else
         return I::empty();
@@ -150,8 +150,8 @@ interval<T, Policies> pow(const interval<T, Policies>& x, int pwr)
     return I::empty();
 
   if (pwr == 0)
-    if (interval_lib::detail::is_zero(x.lower())
-        && interval_lib::detail::is_zero(x.upper()))
+    if (interval_lib::user::is_zero(x.lower())
+        && interval_lib::user::is_zero(x.upper()))
       return I::empty();
     else
       return I(static_cast<T>(1));
@@ -160,14 +160,14 @@ interval<T, Policies> pow(const interval<T, Policies>& x, int pwr)
 
   typename Policies::rounding rnd;
   
-  if (interval_lib::detail::is_neg(x.upper())) {        // [-2,-1]
+  if (interval_lib::user::is_neg(x.upper())) {        // [-2,-1]
     T yl = pow_aux(-x.upper(), pwr, rnd);
     T yu = pow_aux(-x.lower(), pwr, rnd);
     if (pwr & 1)     // [-2,-1]^1
       return I(-yu, -yl, true);
     else             // [-2,-1]^2
       return I(yl, yu, true);
-  } else if (interval_lib::detail::is_neg(x.lower())) { // [-1,1]
+  } else if (interval_lib::user::is_neg(x.lower())) { // [-1,1]
     if (pwr & 1) {   // [-1,1]^1
       return I(-pow_aux(-x.lower(), pwr, rnd), pow_aux(x.upper(), pwr, rnd), true);
     } else {         // [-1,1]^2
@@ -183,10 +183,10 @@ template<class T, class Policies> inline
 interval<T, Policies> sqrt(const interval<T, Policies>& x)
 {
   typedef interval<T, Policies> I;
-  if (interval_lib::detail::test_input(x) || interval_lib::detail::is_neg(x.upper()))
+  if (interval_lib::detail::test_input(x) || interval_lib::user::is_neg(x.upper()))
     return I::empty();
   typename Policies::rounding rnd;
-  T l = (x.lower() <= static_cast<T>(0)) ? static_cast<T>(0) : rnd.sqrt_down(x.lower());
+  T l = !interval_lib::user::is_pos(x.lower()) ? static_cast<T>(0) : rnd.sqrt_down(x.lower());
   return I(l, rnd.sqrt_up(x.upper()), true);
 }
 
@@ -199,9 +199,9 @@ interval<T, Policies> square(const interval<T, Policies>& x)
   typename Policies::rounding rnd;
   const T& xl = x.lower();
   const T& xu = x.upper();
-  if (interval_lib::detail::is_neg(xu))
+  if (interval_lib::user::is_neg(xu))
     return I(rnd.mul_down(xu, xu), rnd.mul_up(xl, xl), true);
-  else if (interval_lib::detail::is_pos(x.lower()))
+  else if (interval_lib::user::is_pos(x.lower()))
     return I(rnd.mul_down(xl, xl), rnd.mul_up(xu, xu), true);
   else
     return I(static_cast<T>(0), (-xl > xu ? rnd.mul_up(xl, xl) : rnd.mul_up(xu, xu)), true);
diff --git a/include/boost/numeric/interval/arith3.hpp b/include/boost/numeric/interval/arith3.hpp
index 6fbf82f..5069b45 100644
--- a/include/boost/numeric/interval/arith3.hpp
+++ b/include/boost/numeric/interval/arith3.hpp
@@ -57,7 +57,7 @@ template<class I> inline
 I div(const typename I::base_type& x, const typename I::base_type& y)
 {
   typedef typename I::traits_type Policies;
-  if (detail::test_input<typename I::base_type, Policies>(x, y) || detail::is_zero(y))
+  if (detail::test_input<typename I::base_type, Policies>(x, y) || user::is_zero(y))
     return I::empty();
   typename Policies::rounding rnd;
   return I(rnd.div_down(x, y), rnd.div_up(x, y), true);
diff --git a/include/boost/numeric/interval/detail/division.hpp b/include/boost/numeric/interval/detail/division.hpp
index f36f586..dcd4eb5 100644
--- a/include/boost/numeric/interval/detail/division.hpp
+++ b/include/boost/numeric/interval/detail/division.hpp
@@ -37,18 +37,18 @@ interval<T, Policies> div_non_zero(const interval<T, Policies>& x,
   const T& xu = x.upper();
   const T& yl = y.lower();
   const T& yu = y.upper();
-  if (is_neg(xu))
-    if (is_neg(yu))
+  if (::boost::numeric::interval_lib::user::is_neg(xu))
+    if (::boost::numeric::interval_lib::user::is_neg(yu))
       return I(rnd.div_down(xu, yl), rnd.div_up(xl, yu), true);
     else
       return I(rnd.div_down(xl, yl), rnd.div_up(xu, yu), true);
-  else if (is_neg(xl))
-    if (is_neg(yu))
+  else if (::boost::numeric::interval_lib::user::is_neg(xl))
+    if (::boost::numeric::interval_lib::user::is_neg(yu))
       return I(rnd.div_down(xu, yu), rnd.div_up(xl, yu), true);
     else
       return I(rnd.div_down(xl, yl), rnd.div_up(xu, yl), true);
   else
-    if (is_neg(yu))
+    if (::boost::numeric::interval_lib::user::is_neg(yu))
       return I(rnd.div_down(xu, yu), rnd.div_up(xl, yl), true);
     else
       return I(rnd.div_down(xl, yu), rnd.div_up(xu, yl), true);
@@ -62,7 +62,7 @@ interval<T, Policies> div_non_zero(const T& x, const interval<T, Policies>& y)
   typedef interval<T, Policies> I;
   const T& yl = y.lower();
   const T& yu = y.upper();
-  if (is_neg(x))
+  if (::boost::numeric::interval_lib::user::is_neg(x))
     return I(rnd.div_down(x, yl), rnd.div_up(x, yu), true);
   else
     return I(rnd.div_down(x, yu), rnd.div_up(x, yl), true);
@@ -71,17 +71,19 @@ interval<T, Policies> div_non_zero(const T& x, const interval<T, Policies>& y)
 template<class T, class Policies> inline
 interval<T, Policies> div_positive(const interval<T, Policies>& x, const T& yu)
 {
-  // assert(yu > T(0));
-  if (is_zero(x.lower()) && is_zero(x.upper())) return x;
+  // assert(::boost::numeric::interval_lib::user::is_pos(yu));
+  if (::boost::numeric::interval_lib::user::is_zero(x.lower()) &&
+      ::boost::numeric::interval_lib::user::is_zero(x.upper()))
+    return x;
   typename Policies::rounding rnd;
   typedef interval<T, Policies> I;
   const T& xl = x.lower();
   const T& xu = x.upper();
   typedef typename Policies::checking checking;
   const T& inf = checking::inf();
-  if (is_neg(xu))
+  if (::boost::numeric::interval_lib::user::is_neg(xu))
     return I(-inf, rnd.div_up(xu, yu), true);
-  else if (is_neg(xl))
+  else if (::boost::numeric::interval_lib::user::is_neg(xl))
     return I(-inf, inf, true);
   else
     return I(rnd.div_down(xl, yu), inf, true);
@@ -90,13 +92,14 @@ interval<T, Policies> div_positive(const interval<T, Policies>& x, const T& yu)
 template<class T, class Policies> inline
 interval<T, Policies> div_positive(const T& x, const T& yu)
 {
-  // assert(yu > T(0));
+  // assert(::boost::numeric::interval_lib::user::is_pos(yu));
   typedef interval<T, Policies> I;
-  if (is_zero(x)) return I(static_cast<T>(0), static_cast<T>(0), true);
+  if (::boost::numeric::interval_lib::user::is_zero(x))
+    return I(static_cast<T>(0), static_cast<T>(0), true);
   typename Policies::rounding rnd;
   typedef typename Policies::checking checking;
   const T& inf = checking::inf();
-  if (is_neg(x))
+  if (::boost::numeric::interval_lib::user::is_neg(x))
     return I(-inf, rnd.div_up(x, yu), true);
   else
     return I(rnd.div_down(x, yu), inf, true);
@@ -105,8 +108,9 @@ interval<T, Policies> div_positive(const T& x, const T& yu)
 template<class T, class Policies> inline
 interval<T, Policies> div_negative(const interval<T, Policies>& x, const T& yl)
 {
-  // assert(yl < T(0));
-  if (is_zero(x.lower()) && is_zero(x.upper()))
+  // assert(::boost::numeric::interval_lib::user::is_neg(yl));
+  if (::boost::numeric::interval_lib::user::is_zero(x.lower()) &&
+      ::boost::numeric::interval_lib::user::is_zero(x.upper()))
     return x;
   typename Policies::rounding rnd;
   typedef interval<T, Policies> I;
@@ -114,9 +118,9 @@ interval<T, Policies> div_negative(const interval<T, Policies>& x, const T& yl)
   const T& xu = x.upper();
   typedef typename Policies::checking checking;
   const T& inf = checking::inf();
-  if (is_neg(xu))
+  if (::boost::numeric::interval_lib::user::is_neg(xu))
     return I(rnd.div_down(xu, yl), inf, true);
-  else if (is_neg(xl))
+  else if (::boost::numeric::interval_lib::user::is_neg(xl))
     return I(-inf, inf, true);
   else
     return I(-inf, rnd.div_up(xl, yl), true);
@@ -125,13 +129,14 @@ interval<T, Policies> div_negative(const interval<T, Policies>& x, const T& yl)
 template<class T, class Policies> inline
 interval<T, Policies> div_negative(const T& x, const T& yl)
 {
-  // assert(yl < T(0));
+  // assert(::boost::numeric::interval_lib::user::is_neg(yl));
   typedef interval<T, Policies> I;
-  if (is_zero(x)) return I(static_cast<T>(0), static_cast<T>(0), true);
+  if (::boost::numeric::interval_lib::user::is_zero(x))
+    return I(static_cast<T>(0), static_cast<T>(0), true);
   typename Policies::rounding rnd;
   typedef typename Policies::checking checking;
   const T& inf = checking::inf();
-  if (is_neg(x))
+  if (::boost::numeric::interval_lib::user::is_neg(x))
     return I(rnd.div_down(x, yl), inf, true);
   else
     return I(-inf, rnd.div_up(x, yl), true);
@@ -140,7 +145,8 @@ interval<T, Policies> div_negative(const T& x, const T& yl)
 template<class T, class Policies> inline
 interval<T, Policies> div_zero(const interval<T, Policies>& x)
 {
-  if (is_zero(x.lower()) && is_zero(x.upper()))
+  if (::boost::numeric::interval_lib::user::is_zero(x.lower()) &&
+      ::boost::numeric::interval_lib::user::is_zero(x.upper()))
     return x;
   else return interval<T, Policies>::whole();
 }
@@ -148,7 +154,8 @@ interval<T, Policies> div_zero(const interval<T, Policies>& x)
 template<class T, class Policies> inline
 interval<T, Policies> div_zero(const T& x)
 {
-  if (is_zero(x)) return interval<T, Policies>(static_cast<T>(0), static_cast<T>(0), true);
+  if (::boost::numeric::interval_lib::user::is_zero(x))
+    return interval<T, Policies>(static_cast<T>(0), static_cast<T>(0), true);
   else return interval<T, Policies>::whole();
 }
 
@@ -156,8 +163,8 @@ template<class T, class Policies> inline
 interval<T, Policies> div_zero_part1(const interval<T, Policies>& x,
                                      const interval<T, Policies>& y, bool& b)
 {
-  // assert(y.lower() < 0 && y.upper() > 0);
-  if (is_zero(x.lower()) && is_zero(x.upper()))
+  // assert(::boost::numeric::interval_lib::user::is_neg(y.lower()) && ::boost::numeric::interval_lib::user::is_pos(y.upper()));
+  if (::boost::numeric::interval_lib::user::is_zero(x.lower()) && ::boost::numeric::interval_lib::user::is_zero(x.upper()))
     { b = false; return x; }
   typename Policies::rounding rnd;
   typedef interval<T, Policies> I;
@@ -167,9 +174,9 @@ interval<T, Policies> div_zero_part1(const interval<T, Policies>& x,
   const T& yu = y.upper();
   typedef typename Policies::checking checking;
   const T& inf = checking::inf();
-  if (is_neg(xu))
+  if (::boost::numeric::interval_lib::user::is_neg(xu))
     { b = true;  return I(-inf, rnd.div_up(xu, yu), true); }
-  else if (is_neg(xl))
+  else if (::boost::numeric::interval_lib::user::is_neg(xl))
     { b = false; return I(-inf, inf, true); }
   else
     { b = true;  return I(-inf, rnd.div_up(xl, yl), true); }
@@ -179,12 +186,12 @@ template<class T, class Policies> inline
 interval<T, Policies> div_zero_part2(const interval<T, Policies>& x,
                                      const interval<T, Policies>& y)
 {
-  // assert(y.lower() < 0 && y.upper() > 0 && (div_zero_part1(x, y, b), b));
+  // assert(::boost::numeric::interval_lib::user::is_neg(y.lower()) && ::boost::numeric::interval_lib::user::is_pos(y.upper()) && (div_zero_part1(x, y, b), b));
   typename Policies::rounding rnd;
   typedef interval<T, Policies> I;
   typedef typename Policies::checking checking;
   const T& inf = checking::inf();
-  if (is_neg(x.upper()))
+  if (::boost::numeric::interval_lib::user::is_neg(x.upper()))
     return I(rnd.div_down(x.upper(), y.lower()), inf, true);
   else
     return I(rnd.div_down(x.lower(), y.upper()), inf, true);
diff --git a/include/boost/numeric/interval/detail/test_input.hpp b/include/boost/numeric/interval/detail/test_input.hpp
index bd454f4..07b1096 100644
--- a/include/boost/numeric/interval/detail/test_input.hpp
+++ b/include/boost/numeric/interval/detail/test_input.hpp
@@ -21,17 +21,21 @@
 namespace boost {
 namespace numeric {
 namespace interval_lib {
+namespace user {
+
+template<class T> inline
+bool is_zero(T const &v) { return v == static_cast<T>(0); }
+
+template<class T> inline
+bool is_neg (T const &v) { return v <  static_cast<T>(0); }
+
+template<class T> inline
+bool is_pos (T const &v) { return v >  static_cast<T>(0); }
+
+} // namespace user
+
 namespace detail {
 
-template<class T> inline
-bool is_neg(const T& x) { return x < static_cast<T>(0); }
-
-template<class T> inline
-bool is_zero(const T& x) { return x == static_cast<T>(0); }
-
-template<class T> inline
-bool is_pos(const T& x) { return x > static_cast<T>(0); }
-
 template<class T, class Policies> inline
 bool test_input(const interval<T, Policies>& x) {
   typedef typename Policies::checking checking;
diff --git a/include/boost/numeric/interval/transc.hpp b/include/boost/numeric/interval/transc.hpp
index ca08ccc..85521f8 100644
--- a/include/boost/numeric/interval/transc.hpp
+++ b/include/boost/numeric/interval/transc.hpp
@@ -47,7 +47,7 @@ interval<T, Policies> log(const interval<T, Policies>& x)
     return I::empty();
   typename Policies::rounding rnd;
   typedef typename Policies::checking checking;
-  T l = (x.lower() <= static_cast<T>(0))
+  T l = !interval_lib::user::is_pos(x.lower())
              ? -checking::inf() : rnd.log_down(x.lower());
   return I(l, rnd.log_up(x.upper()), true);
 }
@@ -176,9 +176,9 @@ interval<T, Policies> cosh(const interval<T, Policies>& x)
   if (interval_lib::detail::test_input(x))
     return I::empty();
   typename Policies::rounding rnd;
-  if (interval_lib::detail::is_neg(x.upper()))
+  if (interval_lib::user::is_neg(x.upper()))
     return I(rnd.cosh_down(x.upper()), rnd.cosh_up(x.lower()), true);
-  else if (!interval_lib::detail::is_neg(x.lower()))
+  else if (!interval_lib::user::is_neg(x.lower()))
     return I(rnd.cosh_down(x.lower()), rnd.cosh_up(x.upper()), true);
   else
     return I(static_cast<T>(0), rnd.cosh_up(-x.lower() > x.upper() ? x.lower() : x.upper()), true);
diff --git a/include/boost/numeric/interval/utility.hpp b/include/boost/numeric/interval/utility.hpp
index 97b1e2d..95355aa 100644
--- a/include/boost/numeric/interval/utility.hpp
+++ b/include/boost/numeric/interval/utility.hpp
@@ -262,8 +262,8 @@ interval<T, Policies> abs(const interval<T, Policies>& x)
   typedef interval<T, Policies> I;
   if (interval_lib::detail::test_input(x))
     return I::empty();
-  if (!interval_lib::detail::is_neg(x.lower())) return x;
-  if (interval_lib::detail::is_neg(x.upper())) return -x;
+  if (!interval_lib::user::is_neg(x.lower())) return x;
+  if (!interval_lib::user::is_pos(x.upper())) return -x;
   return I(static_cast<T>(0), max(-x.lower(), x.upper()), true);
 }