diff --git a/C/stdpreds.c b/C/stdpreds.c
index 5948d0098..45fcc4e96 100644
--- a/C/stdpreds.c
+++ b/C/stdpreds.c
@@ -692,6 +692,10 @@ p_univ( USES_REGS1 )
     return (FALSE);
   if (IsApplTerm(tin)) {
     Functor         fun = FunctorOfTerm(tin);
+    if (IsExtensionFunctor ( fun ) ) {
+      twork = MkPairTerm(tin, MkAtomTerm(AtomNil));
+      return (Yap_unify(twork, ARG2));
+    }
     arity = ArityOfFunctor(fun);
     at = NameOfFunctor(fun);
 #ifdef SFUNC
diff --git a/C/text.c b/C/text.c
index 2a09ca2dc..7dc7d9051 100644
--- a/C/text.c
+++ b/C/text.c
@@ -55,7 +55,25 @@ get_string_from_list( Term t, seq_tv_t *inp, char *s, int atoms USES_REGS)
     max = inp->max;
   }
 
-  if (atoms) {
+  if (TRUE /* atoms == -1 */) {
+    while (t != TermNil) {
+      Term h = HeadOfTerm(t);
+      if (IsAtomTerm(h)) {
+	Atom at;
+	if (IsWideAtom(at = AtomOfTerm(h)))
+	  *s++ = RepAtom(at)->WStrOfAE[0];
+	else
+	  *s++ = (unsigned char)(RepAtom(at)->StrOfAE[0]);
+      } else {
+	*s++  = IntOfTerm(h);
+      }
+      if (--max == 0) {
+	*s++ = 0;
+	return s0;
+      }
+      t = TailOfTerm(t);
+    }
+  } else if (atoms) {
     while (t != TermNil) {
       Atom at;
       if (IsWideAtom(at = AtomOfTerm(HeadOfTerm(t)))) {
@@ -101,7 +119,25 @@ get_wide_from_list( Term t, seq_tv_t *inp, wchar_t *s, int atoms USES_REGS)
     max = inp->max;
   }
 
-  if (atoms) {
+  if (TRUE /* atoms == -1*/) {
+    while (t != TermNil) {
+      Term h = HeadOfTerm(t);
+      if (IsAtomTerm(h)) {
+	Atom at;
+	if (IsWideAtom(at = AtomOfTerm(h)))
+	  *s++ = RepAtom(at)->WStrOfAE[0];
+	else
+	  *s++ = (unsigned char)(RepAtom(at)->StrOfAE[0]);
+      } else {
+	*s++ = IntOfTerm(h);
+      }
+      if (--max == 0) {
+	*s++ = 0;
+	return s0;
+      }
+      t = TailOfTerm(t);
+    }
+  } else if (atoms) {
     while (t != TermNil) {
       Atom at;
       if (IsWideAtom(at = AtomOfTerm(HeadOfTerm(t))))
@@ -166,8 +202,8 @@ SkipListCodes(Term *l, Term **tailp, Int *atoms, int *wide)
 	  length =  -INSTANTIATION_ERROR;
 	} else if (IsAtomTerm(hd)) {
 	  (*atoms)++;
-	  if (*atoms < length)
-	    { *tailp = l; return -TYPE_ERROR_STRING; }
+	  /* if (*atoms < length)
+	     { *tailp = l; return -TYPE_ERROR_STRING; } */
 	  if (IsWideAtom(AtomOfTerm(hd))) {
 	    if ((RepAtom(AtomOfTerm(hd))->WStrOfAE)[1] != '\0') { length = -REPRESENTATION_ERROR_CHARACTER; }
 	    *wide = TRUE;
@@ -177,7 +213,7 @@ SkipListCodes(Term *l, Term **tailp, Int *atoms, int *wide)
 	  }
 	} else if (IsIntTerm(hd)) {
 	  Int ch = IntOfTerm(hd);
-	  if ( *atoms || ch < 0) { *tailp = l; if (*atoms) length = -TYPE_ERROR_STRING; length = -DOMAIN_ERROR_NOT_LESS_THAN_ZERO; }
+	  if (/* *atoms|| */ch < 0) { *tailp = l; /*if (*atoms) length = -TYPE_ERROR_STRING;*/ length = -DOMAIN_ERROR_NOT_LESS_THAN_ZERO; }
 	  else if (ch > 0x80) { *wide = TRUE; }
 	} else {
 	  length = -TYPE_ERROR_INTEGER;
@@ -219,11 +255,12 @@ Yap_ListOfAtomsToBuffer(void *buf, Term t, seq_tv_t *inp, int *widep, size_t *le
     LOCAL_Error_Term = *r;
     return NULL;
   }
-  if (n && !atoms) {
+  /*  if (n && !atoms) {
     LOCAL_Error_Term = t;
     LOCAL_Error_TYPE = TYPE_ERROR_CHARACTER;
     return NULL;
   }
+  */
   *lenp = n;
   if (*widep) {
     wchar_t *s;
diff --git a/C/utilpreds.c b/C/utilpreds.c
index fa8f8e48e..db9e92408 100644
--- a/C/utilpreds.c
+++ b/C/utilpreds.c
@@ -525,26 +525,33 @@ p_copy_term_no_delays( USES_REGS1 )		/* copy term t to a new instance  */
   return(Yap_unify(ARG2,t));
 }
 
+
+
 typedef struct copy_frame {
   CELL *start_cp;
   CELL *end_cp;
   CELL *to;
-#ifdef RATIONAL_TREES
-  CELL oldv;
-  CELL *parent;
-  int ground;
-#endif
 } copy_frame_t;
 
+static Term *
+add_to_list( Term *out_e, Term v, Term t USES_REGS)
+{
+  Term ta[2], tv;
+
+  ta[0] = v;
+  ta[1] = t;
+  *out_e = tv = MkPairTerm(Yap_MkApplTerm( FunctorEq, 2, ta ), TermNil);
+  return RepPair(tv)+1;  
+}
+
 static int
-break_rationals_complex_term(CELL *pt0, CELL *pt0_end, CELL *ptf, CELL *HLow USES_REGS)
+break_rationals_complex_term(CELL *pt0, CELL *pt0_end, CELL *ptf, Term *of, Term oi, CELL *HLow USES_REGS)
 {
 
   struct copy_frame *to_visit0, *to_visit = (struct copy_frame *)Yap_PreAllocCodeSpace();
   CELL *HB0 = HB;
   tr_fr_ptr TR0 = TR;
-  int ground = TRUE;
-  CELL *parent = ptf;
+  CELL new = 0L;
 
   HB = HLow;
   to_visit0 = to_visit;
@@ -555,33 +562,33 @@ break_rationals_complex_term(CELL *pt0, CELL *pt0_end, CELL *ptf, CELL *HLow USE
     ++ pt0;
     ptd0 = pt0;
     d0 = *ptd0;
+    if (new) {
+      /* mark cell as pointing to new copy */
+      /* we can only mark after reading the value of the first argument */
+      MaBind(pt0, new);
+      new = 0L;
+    }
     deref_head(d0, break_rationals_unk);
   break_rationals_nvar:
     {
+      CELL first;
+      CELL *newp;
       if (IsPairTerm(d0)) {
 	CELL *ap2 = RepPair(d0);
-	if (ap2 >= HB && ap2 < HR) {
-	  /* If this is newer than the current term, just reuse */
-	  *ptf++ = d0;
+
+	if (IsVarTerm(first = *ap2) && (newp = (CELL*)first) && newp >= HB && newp < HR) {
+	  // found a marked term:
+	found_term:
+	  if (!IsVarTerm(*newp)) {
+	    Term v = (CELL)newp, t = *newp;
+	    RESET_VARIABLE(newp);
+	    of = add_to_list( of, v, t PASS_REGS); 
+	  }
+	  *ptf++ = (CELL)newp;
 	  continue;
 	} 
-	*ptf = AbsPair(HR);
-	ptf++;
-#ifdef RATIONAL_TREES
-	if (to_visit+1 >= (struct copy_frame *)AuxSp) {
-	  goto heap_overflow;
-	}
-	to_visit->start_cp = pt0;
-	to_visit->end_cp = pt0_end;
-	to_visit->to = ptf;
-	to_visit->oldv = *pt0;
-	to_visit->ground = ground;
-	to_visit->parent = parent;
-	parent = ptf-1;
-	/* fool the system into thinking we had a variable there */
-	*pt0 = TermFoundVar;
-	to_visit ++;
-#else
+	new = (CELL)ptf;
+	*ptf++ = AbsPair(HR);
 	if (pt0 < pt0_end) {
 	  if (to_visit+1 >= (struct copy_frame *)AuxSp) {
 	    goto heap_overflow;
@@ -589,11 +596,8 @@ break_rationals_complex_term(CELL *pt0, CELL *pt0_end, CELL *ptf, CELL *HLow USE
 	  to_visit->start_cp = pt0;
 	  to_visit->end_cp = pt0_end;
 	  to_visit->to = ptf;
-	  to_visit->ground = ground;
 	  to_visit ++;
 	}
-#endif
-	ground = TRUE;
 	pt0 = ap2 - 1;
 	pt0_end = ap2 + 1;
 	ptf = HR;
@@ -606,35 +610,18 @@ break_rationals_complex_term(CELL *pt0, CELL *pt0_end, CELL *ptf, CELL *HLow USE
 	register CELL *ap2;
 	/* store the terms to visit */
 	ap2 = RepAppl(d0);
-	if (ap2 >= HB && ap2 <= HR) {
-	  /* If this is newer than the current term, just reuse */
-	  *ptf++ = d0;
-	  continue;
-	} 
 	f = (Functor)(*ap2);
-
 	if (IsExtensionFunctor(f)) {
-	  *ptf++ = d0;  /* you can just copy extensions, what about DB?*/
+	  *ptf++ = d0;  /* you can just share extensions, what about DB? */
 	  continue;
 	}
-	*ptf = AbsAppl(HR);
-	ptf++;
+	if (IsVarTerm(first = ap2[1]) && (newp = (CELL*)first) && newp >= HB && newp < HR) {
+	  goto found_term;
+	} 
+	// new 
 	/* store the terms to visit */
-#ifdef RATIONAL_TREES
-	if (to_visit+1 >= (struct copy_frame *)AuxSp) {
-	  goto heap_overflow;
-	}
-	to_visit->start_cp = pt0;
-	to_visit->end_cp = pt0_end;
-	to_visit->to = ptf;
-	to_visit->oldv = *pt0;
-	to_visit->ground = ground;
-	to_visit->parent = parent;
-	parent = ptf-1;
-	/* fool the system into thinking we had a variable there */
-	*pt0 = TermFoundVar;
-	to_visit ++;
-#else
+	new = (CELL)ptf;
+	*ptf++ = AbsAppl(HR);
 	if (pt0 < pt0_end) {
 	  if (to_visit+1 >= (struct copy_frame *)AuxSp) {
 	    goto heap_overflow;
@@ -642,10 +629,8 @@ break_rationals_complex_term(CELL *pt0, CELL *pt0_end, CELL *ptf, CELL *HLow USE
 	  to_visit->start_cp = pt0;
 	  to_visit->end_cp = pt0_end;
 	  to_visit->to = ptf;
-	  to_visit->ground = ground;
 	  to_visit ++;
 	}
-#endif
 	d0 = ArityOfFunctor(f);
 	pt0 = ap2;
 	pt0_end = ap2 + d0;
@@ -658,61 +643,29 @@ break_rationals_complex_term(CELL *pt0, CELL *pt0_end, CELL *ptf, CELL *HLow USE
 	}
       } else {
 	/* just copy atoms or integers */
-	if (d0 == TermFoundVar) {
-	  struct copy_frame *visited = to_visit-1;
-	  CELL *end = pt0_end;
-	  RESET_VARIABLE(ptf);
-	  while (visited >= to_visit0) {
-	    if (visited->end_cp == end) {
-	      Term t[1];
-	      t[0] = MkIntegerTerm(to_visit-visited);
-	      *parent = Yap_MkApplTerm(FunctorLOOP,1,t);
-	      break;
-	    }
-	    visited--;
-	  }
-	  ptf++;
-	  ground = FALSE;
-	} else {
-	  *ptf++ = d0;
-	}
+	*ptf++ = d0;
       }
       continue;
     }
 
     derefa_body(d0, ptd0, break_rationals_unk, break_rationals_nvar);
-    /* we have already found this cell */
-    *ptf++ = (CELL) ptd0;
+    *ptf++ = d0;
   }
   /* Do we still have compound terms to visit */
   if (to_visit > to_visit0) {
     to_visit --;
-    if (ground) {
-      CELL old = to_visit->oldv;
-      CELL *newp = to_visit->to-1;
-      CELL new = *newp;
-
-      *newp = old;
-      if (IsApplTerm(new))
-	HR = RepAppl(new);
-      else
-	HR = RepPair(new);
-    }
     pt0 = to_visit->start_cp;
     pt0_end = to_visit->end_cp;
     ptf = to_visit->to;
-    parent = to_visit->parent;
-#ifdef RATIONAL_TREES
-    *pt0 = to_visit->oldv;
-#endif
-    ground = (ground && to_visit->ground);
     goto loop;
   }
 
   /* restore our nice, friendly, term to its original state */
-  clean_dirty_tr(TR0 PASS_REGS);
   HB = HB0;
-  return ground;
+  reset_trail(TR0);
+  RESET_VARIABLE(of);
+  Yap_unify((CELL)of, oi);
+  return TRUE;
 
  overflow:
   /* oops, we're in trouble */
@@ -726,8 +679,6 @@ break_rationals_complex_term(CELL *pt0, CELL *pt0_end, CELL *ptf, CELL *HLow USE
     pt0 = to_visit->start_cp;
     pt0_end = to_visit->end_cp;
     ptf = to_visit->to;
-    parent = to_visit->parent;
-    *pt0 = to_visit->oldv;
   }
 #endif
   reset_trail(TR0);
@@ -746,8 +697,6 @@ break_rationals_complex_term(CELL *pt0, CELL *pt0_end, CELL *ptf, CELL *HLow USE
     pt0 = to_visit->start_cp;
     pt0_end = to_visit->end_cp;
     ptf = to_visit->to;
-    parent = to_visit->parent;
-    *pt0 = to_visit->oldv;
   }
 #endif
   reset_trail(TR0);
@@ -757,7 +706,7 @@ break_rationals_complex_term(CELL *pt0, CELL *pt0_end, CELL *ptf, CELL *HLow USE
 
 
 static Term
-BreakRational(Term inp, UInt arity USES_REGS) {
+BreakRational(Term inp, UInt arity, Term *of, Term oi USES_REGS) {
   Term t = Deref(inp);
   tr_fr_ptr TR0 = TR;
 
@@ -765,383 +714,42 @@ BreakRational(Term inp, UInt arity USES_REGS) {
     return t;
   } else if (IsPrimitiveTerm(t)) {
     return t;
-  } else if (IsPairTerm(t)) {
-    Term tf;
+  } else  {
     CELL *ap;
-    CELL *Hi;
+    CELL *Hi = HR;
 
-  restart_list:
-    ap = RepPair(t);
-    Hi = HR;
-    tf = AbsPair(HR);
-    HR += 2;
+  restart_term:
+    ap = &t;
+    Hi = HR++;
     {
       int res;
-      if ((res = break_rationals_complex_term(ap-1, ap+1, Hi, Hi PASS_REGS)) < 0) {
+
+      if ((res = break_rationals_complex_term(ap-1, ap, Hi, of, oi, Hi PASS_REGS)) < 0) {
 	HR = Hi;
 	if ((t = handle_cp_overflow(res, TR0, arity, t))== 0L)
 	  return FALSE;
-	goto restart_list;
-      } else if (res) {
-	HR = Hi;
-	return t;
+	goto restart_term;
       }
     }
-    return tf;
-  } else {
-    Functor f = FunctorOfTerm(t);
-    Term tf;
-    CELL *HB0;
-    CELL *ap;
-
-  restart_appl:
-    f = FunctorOfTerm(t);
-    HB0 = HR;
-    ap = RepAppl(t);
-    tf = AbsAppl(HR);
-    HR[0] = (CELL)f;
-    HR += 1+ArityOfFunctor(f);
-    if (HR > ASP-128) {
-      HR = HB0;
-      if ((t = handle_cp_overflow(-1, TR0, arity, t))== 0L)
-	return FALSE;
-      goto restart_appl;
-    } else {
-      int res;
-
-      if ((res = break_rationals_complex_term(ap, ap+ArityOfFunctor(f), HB0+1, HB0 PASS_REGS)) < 0) {
-	HR = HB0;
-	if ((t = handle_cp_overflow(res, TR0, arity, t))== 0L)
-	  return FALSE;
-	goto restart_appl;
-      } else if (res && FunctorOfTerm(t) != FunctorMutable) {
-	HR = HB0;
-	return t;
-      }
-    }
-    return tf;
+    return Hi[0];
   }
 }
  
 static Int
 p_break_rational( USES_REGS1 ) 
 {
-  return Yap_unify(ARG2, BreakRational(ARG1, 2 PASS_REGS));
+  Term tf;
+  return Yap_unify(ARG2, BreakRational(ARG1, 4, &tf, ARG4 PASS_REGS)) &&
+    Yap_unify(tf, ARG3);
 }
 
 
-typedef struct restore_frame {
-  CELL *start_cp;
-  CELL *end_cp;
-  CELL *to;
-#ifdef RATIONAL_TREES
-  CELL oldv;
-  CELL *parent;
-  int ground;
-  int term_type;
-#endif
-} restore_frame_t;
-
-static int
-restore_rationals_complex_term(CELL *pt0, CELL *pt0_end, CELL *ptf, CELL *HLow, int pair USES_REGS)
-{
-
-  struct restore_frame *to_visit0, *to_visit = (struct restore_frame *)Yap_PreAllocCodeSpace();
-  CELL *HB0 = HB;
-  tr_fr_ptr TR0 = TR;
-  int ground = TRUE;
-  CELL *parent = ptf;
-
-  HB = HLow;
-  to_visit0 = to_visit;
- loop:
-  while (pt0 < pt0_end) {
-    register CELL d0;
-    register CELL *ptd0;
-    ++ pt0;
-    ptd0 = pt0;
-    d0 = *ptd0;
-    deref_head(d0, restore_rationals_unk);
-  restore_rationals_nvar:
-    {
-      if (IsPairTerm(d0)) {
-	CELL *ap2 = RepPair(d0);
-	if (ap2 >= HB && ap2 < HR) {
-	  /* If this is newer than the current term, just reuse */
-	  *ptf++ = d0;
-	  continue;
-	} 
-	*ptf = AbsPair(HR);
-	ptf++;
-#ifdef RATIONAL_TREES
-	if (to_visit+1 >= (struct restore_frame *)AuxSp) {
-	  goto heap_overflow;
-	}
-	to_visit->start_cp = pt0;
-	to_visit->end_cp = pt0_end;
-	to_visit->to = ptf;
-	to_visit->oldv = *pt0;
-	to_visit->ground = ground;
-	to_visit->parent = parent;
-	to_visit->term_type = pair;
-	parent = ptf;
-	/* fool the system into thinking we had a variable there */
-	*pt0 = TermFoundVar;
-	to_visit ++;
-#else
-	if (pt0 < pt0_end) {
-	  if (to_visit+1 >= (struct restore_frame *)AuxSp) {
-	    goto heap_overflow;
-	  }
-	  to_visit->start_cp = pt0;
-	  to_visit->end_cp = pt0_end;
-	  to_visit->to = ptf;
-	  to_visit->ground = ground;
-	  to_visit ++;
-	}
-#endif
-	ground = TRUE;
-	pair = TRUE;
-	pt0 = ap2 - 1;
-	pt0_end = ap2 + 1;
-	ptf = HR;
-	HR += 2;
-	if (HR > ASP - 2048) {
-	  goto overflow;
-	}
-      } else if (IsApplTerm(d0)) {
-	register Functor f;
-	register CELL *ap2;
-	/* store the terms to visit */
-	ap2 = RepAppl(d0);
-	if (ap2 >= HB && ap2 <= HR) {
-	  /* If this is newer than the current term, just reuse */
-	  *ptf++ = d0;
-	  continue;
-	} 
-	f = (Functor)(*ap2);
-
-	if (IsExtensionFunctor(f)) {
-	  *ptf++ = d0;  /* you can just copy extensions, what about DB?*/
-	  continue;
-	} else if (f == FunctorLOOP) {
-	  Int nlevels = IntegerOfTerm(ap2[1])-1;
-	  struct restore_frame *visited = to_visit-nlevels;
-	  CELL *p;
-	  int type_pair;
-
-	  if (nlevels) {
-	    p = visited->parent;
-	    type_pair = visited->term_type;
-	  } else {
-	    p = parent;
-	    type_pair = pair;
-	  }
-	  if (type_pair) {
-	    *ptf++ = AbsPair(p);
-	  } else {
-	    *ptf++ = AbsAppl(p-1);
-	  }
-	  ground = FALSE;
-	  continue;
-	} 
-	*ptf = AbsAppl(HR);
-	ptf++;
-	/* store the terms to visit */
-#ifdef RATIONAL_TREES
-	if (to_visit+1 >= (struct restore_frame *)AuxSp) {
-	  goto heap_overflow;
-	}
-	to_visit->start_cp = pt0;
-	to_visit->end_cp = pt0_end;
-	to_visit->to = ptf;
-	to_visit->oldv = *pt0;
-	to_visit->ground = ground;
-	to_visit->parent = parent;
-	to_visit->term_type = pair;
-	parent = ptf;
-	/* fool the system into thinking we had a variable there */
-	*pt0 = TermFoundVar;
-	to_visit ++;
-#else
-	if (pt0 < pt0_end) {
-	  if (to_visit+1 >= (struct restore_frame *)AuxSp) {
-	    goto heap_overflow;
-	  }
-	  to_visit->start_cp = pt0;
-	  to_visit->end_cp = pt0_end;
-	  to_visit->to = ptf;
-	  to_visit->ground = ground;
-	  to_visit ++;
-	}
-#endif
-	d0 = ArityOfFunctor(f);
-	pt0 = ap2;
-	pt0_end = ap2 + d0;
-	/* store the functor for the new term */
-	HR[0] = (CELL)f;
-	ptf = HR+1;
-	HR += 1+d0;
-	pair = FALSE;
-	if (HR > ASP - 2048) {
-	  goto overflow;
-	}
-      } else {
-	*ptf++ = d0;
-      }
-      continue;
-    }
-
-    derefa_body(d0, ptd0, restore_rationals_unk, restore_rationals_nvar);
-    /* we have already found this cell */
-    *ptf++ = (CELL) ptd0;
-  }
-  /* Do we still have compound terms to visit */
-  if (to_visit > to_visit0) {
-    to_visit --;
-    if (ground) {
-      CELL old = to_visit->oldv;
-      CELL *newp = to_visit->to-1;
-      CELL new = *newp;
-
-      *newp = old;
-      if (IsApplTerm(new))
-	HR = RepAppl(new);
-      else
-	HR = RepPair(new);
-    }
-    pt0 = to_visit->start_cp;
-    pt0_end = to_visit->end_cp;
-    ptf = to_visit->to;
-#ifdef RATIONAL_TREES
-    parent = to_visit->parent;
-    pair = to_visit->term_type;
-    *pt0 = to_visit->oldv;
-#endif
-    ground = (ground && to_visit->ground);
-    goto loop;
-  }
-
-  /* restore our nice, friendly, term to its original state */
-  clean_dirty_tr(TR0 PASS_REGS);
-  HB = HB0;
-  return ground;
-
- overflow:
-  /* oops, we're in trouble */
-  HR = HLow;
-  /* we've done it */
-  /* restore our nice, friendly, term to its original state */
-  HB = HB0;
-#ifdef RATIONAL_TREES
-  while (to_visit > to_visit0) {
-    to_visit --;
-    pt0 = to_visit->start_cp;
-    pt0_end = to_visit->end_cp;
-    ptf = to_visit->to;
-    parent = to_visit->parent;
-    pair = to_visit->term_type;
-    *pt0 = to_visit->oldv;
-  }
-#endif
-  reset_trail(TR0);
-  /* follow chain of multi-assigned variables */
-  return -1;
-
- heap_overflow:
-  /* oops, we're in trouble */
-  HR = HLow;
-  /* we've done it */
-  /* restore our nice, friendly, term to its original state */
-  HB = HB0;
-#ifdef RATIONAL_TREES
-  while (to_visit > to_visit0) {
-    to_visit --;
-    pt0 = to_visit->start_cp;
-    pt0_end = to_visit->end_cp;
-    ptf = to_visit->to;
-    parent = to_visit->parent;
-    pair = to_visit->term_type;
-    *pt0 = to_visit->oldv;
-  }
-#endif
-  reset_trail(TR0);
-  LOCAL_Error_Size = (ADDR)AuxSp-(ADDR)to_visit0;
-  return -3;
-}
-
-
-static Term
-RestoreRational(Term inp, UInt arity USES_REGS) {
-  Term t = Deref(inp);
-  tr_fr_ptr TR0 = TR;
-
-  if (IsVarTerm(t)) {
-    return t;
-  } else if (IsPrimitiveTerm(t)) {
-    return t;
-  } else if (IsPairTerm(t)) {
-    Term tf;
-    CELL *ap;
-    CELL *Hi;
-
-  restart_list:
-    ap = RepPair(t);
-    Hi = HR;
-    tf = AbsPair(HR);
-    HR += 2;
-    {
-      int res;
-      if ((res = restore_rationals_complex_term(ap-1, ap+1, Hi, Hi, TRUE PASS_REGS)) < 0) {
-	HR = Hi;
-	if ((t = handle_cp_overflow(res, TR0, arity, t))== 0L)
-	  return FALSE;
-	goto restart_list;
-      } else if (res) {
-	HR = Hi;
-	return t;
-      }
-    }
-    return tf;
-  } else {
-    Functor f = FunctorOfTerm(t);
-    Term tf;
-    CELL *HB0;
-    CELL *ap;
-
-  restart_appl:
-    f = FunctorOfTerm(t);
-    HB0 = HR;
-    ap = RepAppl(t);
-    tf = AbsAppl(HR);
-    HR[0] = (CELL)f;
-    HR += 1+ArityOfFunctor(f);
-    if (HR > ASP-128) {
-      HR = HB0;
-      if ((t = handle_cp_overflow(-1, TR0, arity, t))== 0L)
-	return FALSE;
-      goto restart_appl;
-    } else {
-      int res;
-
-      if ((res = restore_rationals_complex_term(ap, ap+ArityOfFunctor(f), HB0+1, HB0, FALSE PASS_REGS)) < 0) {
-	HR = HB0;
-	if ((t = handle_cp_overflow(res, TR0, arity, t))== 0L)
-	  return FALSE;
-	goto restart_appl;
-      } else if (res && FunctorOfTerm(t) != FunctorMutable) {
-	HR = HB0;
-	return t;
-      }
-    }
-    return tf;
-  }
-}
- 
 static Int
-p_restore_rational( USES_REGS1 ) 
+p_break_rational3( USES_REGS1 ) 
 {
-  return Yap_unify(ARG2, RestoreRational(ARG1, 2 PASS_REGS));
+  Term tf;
+  return Yap_unify(ARG2, BreakRational(ARG1, 4, &tf, TermNil PASS_REGS)) &&
+    Yap_unify(tf, ARG3);
 }
 
 
@@ -5639,8 +5247,8 @@ void Yap_InitUtilCPreds(void)
   Yap_InitCPred("term_attvars", 2, p_term_attvars, 0);
   Yap_InitCPred("is_list", 1, p_is_list, SafePredFlag|TestPredFlag);
   Yap_InitCPred("$is_list_or_partial_list", 1, p_is_list_or_partial_list, SafePredFlag|TestPredFlag);
-  Yap_InitCPred("rational_term_to_tree", 2, p_break_rational, 0);
-  Yap_InitCPred("tree_to_rational_term", 2, p_restore_rational, 0);
+  Yap_InitCPred("rational_term_to_tree", 4, p_break_rational, 0);
+  Yap_InitCPred("term_factorized", 3, p_break_rational3, 0);
   Yap_InitCPred("=@=", 2, p_variant, 0);
   Yap_InitCPred("numbervars", 3, p_numbervars, 0);
   Yap_InitCPred("unnumbervars", 2, p_unnumbervars, 0);