diff --git a/src/util/cooperate.cpp b/src/util/cooperate.cpp
index 2b2e7958e..df8f67968 100644
--- a/src/util/cooperate.cpp
+++ b/src/util/cooperate.cpp
@@ -16,6 +16,8 @@ Author:
 Notes:
 
 --*/
+
+#ifndef _NO_OMP_
 #include "util/cooperate.h"
 #include "util/trace.h"
 #include "util/debug.h"
@@ -36,7 +38,7 @@ struct cooperation_lock {
     }
 };
 
-cooperation_lock g_lock;
+static cooperation_lock g_lock;
 
 bool cooperation_ctx::g_cooperate = false;
 
@@ -59,29 +61,4 @@ void cooperation_ctx::checkpoint(char const * task) {
     }
 }
 
-cooperation_section::cooperation_section() {
-    SASSERT(!cooperation_ctx::enabled());
-    SASSERT(!omp_in_parallel());
-    cooperation_ctx::g_cooperate = true;
-}
-
-cooperation_section::~cooperation_section() {
-    SASSERT(cooperation_ctx::enabled());
-    cooperation_ctx::g_cooperate = false;
-}
-
-init_task::init_task(char const * task) {
-    SASSERT(cooperation_ctx::enabled());
-    SASSERT(omp_in_parallel());
-    cooperation_ctx::checkpoint(task);
-}
-
-init_task::~init_task() {
-    int  tid      = omp_get_thread_num();
-    if (g_lock.m_owner_thread == tid) {
-        g_lock.m_owner_thread = -1;
-        omp_unset_nest_lock(&(g_lock.m_lock));
-    }
-}
-
-
+#endif
diff --git a/src/util/cooperate.h b/src/util/cooperate.h
index af2cff55c..6220c4c51 100644
--- a/src/util/cooperate.h
+++ b/src/util/cooperate.h
@@ -19,10 +19,9 @@ Notes:
 #ifndef COOPERATE_H_
 #define COOPERATE_H_
 
-class cooperation_section;
+#ifndef _NO_OMP_
 
 class cooperation_ctx {
-    friend class cooperation_section;
     static bool g_cooperate;
 public:
     static bool enabled() { return g_cooperate; }
@@ -33,18 +32,8 @@ inline void cooperate(char const * task) {
     if (cooperation_ctx::enabled()) cooperation_ctx::checkpoint(task);
 }
 
-// must be declared before "#pragma parallel" to enable cooperation 
-class cooperation_section {
-public:
-    cooperation_section();
-    ~cooperation_section();
-};
-
-// must be first declaration inside "#pragma parallel for"
-class init_task {
-public:
-    init_task(char const * task);
-    ~init_task();
-};
+#else
+inline void cooperate(char const *) {}
+#endif
 
 #endif
diff --git a/src/util/mpq.h b/src/util/mpq.h
index b7bdbf400..77301371d 100644
--- a/src/util/mpq.h
+++ b/src/util/mpq.h
@@ -814,9 +814,6 @@ public:
     bool is_even(mpz const & a) { return mpz_manager<SYNCH>::is_even(a); }
 public:
     bool is_even(mpq const & a) { return is_int(a) && is_even(a.m_num); }
-
-    friend bool operator==(mpq const & a, mpq const & b) ;
-    friend bool operator>=(mpq const & a, mpq const & b);
 };
 
 typedef mpq_manager<true> synch_mpq_manager;