diff --git a/src/api/js/src/high-level/high-level.test.ts b/src/api/js/src/high-level/high-level.test.ts
index fb8805d99..e9a2b46e7 100644
--- a/src/api/js/src/high-level/high-level.test.ts
+++ b/src/api/js/src/high-level/high-level.test.ts
@@ -890,4 +890,74 @@ describe('high-level', () => {
       expect(model.eval(z).eqIdentity(Int.val(5))).toBeTruthy();
     });
   });
+
+  describe('datatypes', () => {
+    it('should create simple enum datatype', async () => {
+      const { Datatype, Int, Bool, Solver } = api.Context('main');
+
+      // Create a simple Color enum datatype
+      const Color = Datatype('Color');
+      Color.declare('red');
+      Color.declare('green');
+      Color.declare('blue');
+      
+      const ColorSort = Color.create();
+      
+      // Test that we can access the constructors
+      expect(typeof (ColorSort as any).red).not.toBe('undefined');
+      expect(typeof (ColorSort as any).green).not.toBe('undefined');
+      expect(typeof (ColorSort as any).blue).not.toBe('undefined');
+      
+      // Test that we can access the recognizers
+      expect(typeof (ColorSort as any).is_red).not.toBe('undefined');
+      expect(typeof (ColorSort as any).is_green).not.toBe('undefined');
+      expect(typeof (ColorSort as any).is_blue).not.toBe('undefined');
+    });
+
+    it('should create recursive list datatype', async () => {
+      const { Datatype, Int, Solver } = api.Context('main');
+
+      // Create a recursive List datatype like in the Python example
+      const List = Datatype('List');
+      List.declare('cons', ['car', Int.sort()], ['cdr', List]);
+      List.declare('nil');
+      
+      const ListSort = List.create();
+      
+      // Test that constructors and accessors exist
+      expect(typeof (ListSort as any).cons).not.toBe('undefined');
+      expect(typeof (ListSort as any).nil).not.toBe('undefined');
+      expect(typeof (ListSort as any).is_cons).not.toBe('undefined');
+      expect(typeof (ListSort as any).is_nil).not.toBe('undefined');
+      expect(typeof (ListSort as any).car).not.toBe('undefined');
+      expect(typeof (ListSort as any).cdr).not.toBe('undefined');
+    });
+
+    it('should create mutually recursive tree datatypes', async () => {
+      const { Datatype, Int } = api.Context('main');
+
+      // Create mutually recursive Tree and TreeList datatypes
+      const Tree = Datatype('Tree');
+      const TreeList = Datatype('TreeList');
+      
+      Tree.declare('leaf', ['value', Int.sort()]);
+      Tree.declare('node', ['children', TreeList]);
+      TreeList.declare('nil');
+      TreeList.declare('cons', ['car', Tree], ['cdr', TreeList]);
+      
+      const [TreeSort, TreeListSort] = Datatype.createDatatypes(Tree, TreeList);
+      
+      // Test that both datatypes have their constructors
+      expect(typeof (TreeSort as any).leaf).not.toBe('undefined');
+      expect(typeof (TreeSort as any).node).not.toBe('undefined');
+      expect(typeof (TreeListSort as any).nil).not.toBe('undefined');
+      expect(typeof (TreeListSort as any).cons).not.toBe('undefined');
+      
+      // Test accessors exist
+      expect(typeof (TreeSort as any).value).not.toBe('undefined');
+      expect(typeof (TreeSort as any).children).not.toBe('undefined');
+      expect(typeof (TreeListSort as any).car).not.toBe('undefined');
+      expect(typeof (TreeListSort as any).cdr).not.toBe('undefined');
+    });
+  });
 });
diff --git a/src/api/js/src/high-level/high-level.ts b/src/api/js/src/high-level/high-level.ts
index 7d19df982..f53f2d8ca 100644
--- a/src/api/js/src/high-level/high-level.ts
+++ b/src/api/js/src/high-level/high-level.ts
@@ -17,6 +17,8 @@ import {
   Z3_ast_print_mode,
   Z3_ast_vector,
   Z3_context,
+  Z3_constructor,
+  Z3_constructor_list,
   Z3_decl_kind,
   Z3_error_code,
   Z3_func_decl,
@@ -88,6 +90,10 @@ import {
   FuncEntry,
   SMTSetSort,
   SMTSet,
+  Datatype,
+  DatatypeSort,
+  DatatypeExpr,
+  DatatypeCreation,
 } from './types';
 import { allSatisfy, assert, assertExhaustive } from './utils';
 
@@ -825,6 +831,17 @@ export function createApi(Z3: Z3Core): Z3HighLevel {
       }
     }
 
+    const Datatype = Object.assign(
+      (name: string): DatatypeImpl => {
+        return new DatatypeImpl(ctx, name);
+      },
+      {
+        createDatatypes(...datatypes: DatatypeImpl[]): DatatypeSortImpl[] {
+          return createDatatypes(...datatypes);
+        }
+      }
+    );
+
     ////////////////
     // Operations //
     ////////////////
@@ -2647,6 +2664,185 @@ export function createApi(Z3: Z3Core): Z3HighLevel {
       }
     }
 
+    ////////////////////////////
+    // Datatypes
+    ////////////////////////////
+
+    class DatatypeImpl implements Datatype<Name> {
+      readonly ctx: Context<Name>;
+      readonly name: string;
+      public constructors: Array<[string, Array<[string, Sort<Name> | Datatype<Name>]>]> = [];
+
+      constructor(ctx: Context<Name>, name: string) {
+        this.ctx = ctx;
+        this.name = name;
+      }
+
+      declare(name: string, ...fields: Array<[string, Sort<Name> | Datatype<Name>]>): this {
+        this.constructors.push([name, fields]);
+        return this;
+      }
+
+      create(): DatatypeSort<Name> {
+        const datatypes = createDatatypes(this);
+        return datatypes[0];
+      }
+    }
+
+    class DatatypeSortImpl extends SortImpl implements DatatypeSort<Name> {
+      declare readonly __typename: DatatypeSort['__typename'];
+
+      numConstructors(): number {
+        return Z3.get_datatype_sort_num_constructors(contextPtr, this.ptr);
+      }
+
+      constructorDecl(idx: number): FuncDecl<Name> {
+        const ptr = Z3.get_datatype_sort_constructor(contextPtr, this.ptr, idx);
+        return new FuncDeclImpl(ptr);
+      }
+
+      recognizer(idx: number): FuncDecl<Name> {
+        const ptr = Z3.get_datatype_sort_recognizer(contextPtr, this.ptr, idx);
+        return new FuncDeclImpl(ptr);
+      }
+
+      accessor(constructorIdx: number, accessorIdx: number): FuncDecl<Name> {
+        const ptr = Z3.get_datatype_sort_constructor_accessor(contextPtr, this.ptr, constructorIdx, accessorIdx);
+        return new FuncDeclImpl(ptr);
+      }
+
+      cast(other: CoercibleToExpr<Name>): DatatypeExpr<Name>;
+      cast(other: DatatypeExpr<Name>): DatatypeExpr<Name>;
+      cast(other: CoercibleToExpr<Name> | DatatypeExpr<Name>): DatatypeExpr<Name> {
+        if (isExpr(other)) {
+          assert(this.eqIdentity(other.sort), 'Value cannot be converted to this datatype');
+          return other as DatatypeExpr<Name>;
+        }
+        throw new Error('Cannot coerce value to datatype expression');
+      }
+
+      subsort(other: Sort<Name>) {
+        _assertContext(other.ctx);
+        return this.eqIdentity(other);
+      }
+    }
+
+    class DatatypeExprImpl extends ExprImpl<Z3_ast, DatatypeSortImpl> implements DatatypeExpr<Name> {
+      declare readonly __typename: DatatypeExpr['__typename'];
+    }
+
+    function createDatatypes(...datatypes: DatatypeImpl[]): DatatypeSortImpl[] {
+      if (datatypes.length === 0) {
+        throw new Error('At least one datatype must be provided');
+      }
+
+      // All datatypes must be from the same context
+      const dtCtx = datatypes[0].ctx;
+      for (const dt of datatypes) {
+        if (dt.ctx !== dtCtx) {
+          throw new Error('All datatypes must be from the same context');
+        }
+      }
+
+      const sortNames = datatypes.map(dt => dt.name);
+      const constructorLists: Z3_constructor_list[] = [];
+      const scopedConstructors: Z3_constructor[] = [];
+
+      try {
+        // Create constructor lists for each datatype
+        for (const dt of datatypes) {
+          const constructors: Z3_constructor[] = [];
+
+          for (const [constructorName, fields] of dt.constructors) {
+            const fieldNames: string[] = [];
+            const fieldSorts: Z3_sort[] = [];
+            const fieldRefs: number[] = [];
+
+            for (const [fieldName, fieldSort] of fields) {
+              fieldNames.push(fieldName);
+              
+              if (fieldSort instanceof DatatypeImpl) {
+                // Reference to another datatype being defined
+                const refIndex = datatypes.indexOf(fieldSort);
+                if (refIndex === -1) {
+                  throw new Error(`Referenced datatype "${fieldSort.name}" not found in datatypes being created`);
+                }
+                // For recursive references, we pass null and the ref index
+                fieldSorts.push(null as any); // null will be handled by the Z3 API
+                fieldRefs.push(refIndex);
+              } else {
+                // Regular sort
+                fieldSorts.push((fieldSort as Sort<Name>).ptr);
+                fieldRefs.push(0);
+              }
+            }
+
+            const constructor = Z3.mk_constructor(
+              contextPtr,
+              Z3.mk_string_symbol(contextPtr, constructorName),
+              Z3.mk_string_symbol(contextPtr, `is_${constructorName}`),
+              fieldNames.map(name => Z3.mk_string_symbol(contextPtr, name)),
+              fieldSorts,
+              fieldRefs
+            );
+            constructors.push(constructor);
+            scopedConstructors.push(constructor);
+          }
+
+          const constructorList = Z3.mk_constructor_list(contextPtr, constructors);
+          constructorLists.push(constructorList);
+        }
+
+        // Create the datatypes
+        const sortSymbols = sortNames.map(name => Z3.mk_string_symbol(contextPtr, name));
+        const resultSorts = Z3.mk_datatypes(contextPtr, sortSymbols, constructorLists);
+
+        // Create DatatypeSortImpl instances
+        const results: DatatypeSortImpl[] = [];
+        for (let i = 0; i < resultSorts.length; i++) {
+          const sortImpl = new DatatypeSortImpl(resultSorts[i]);
+          
+          // Attach constructor, recognizer, and accessor functions dynamically
+          const numConstructors = sortImpl.numConstructors();
+          for (let j = 0; j < numConstructors; j++) {
+            const constructor = sortImpl.constructorDecl(j);
+            const recognizer = sortImpl.recognizer(j);
+            const constructorName = constructor.name().toString();
+            
+            // Attach constructor function
+            if (constructor.arity() === 0) {
+              // Nullary constructor (constant)
+              (sortImpl as any)[constructorName] = constructor.call();
+            } else {
+              (sortImpl as any)[constructorName] = constructor;
+            }
+            
+            // Attach recognizer function
+            (sortImpl as any)[`is_${constructorName}`] = recognizer;
+            
+            // Attach accessor functions
+            for (let k = 0; k < constructor.arity(); k++) {
+              const accessor = sortImpl.accessor(j, k);
+              const accessorName = accessor.name().toString();
+              (sortImpl as any)[accessorName] = accessor;
+            }
+          }
+          
+          results.push(sortImpl);
+        }
+
+        return results;
+      } finally {
+        // Clean up resources
+        for (const constructor of scopedConstructors) {
+          Z3.del_constructor(contextPtr, constructor);
+        }
+        for (const constructorList of constructorLists) {
+          Z3.del_constructor_list(contextPtr, constructorList);
+        }
+      }
+    }
+
     class QuantifierImpl<
         QVarSorts extends NonEmptySortArray<Name>,
         QSort extends BoolSort<Name> | SMTArraySort<Name, QVarSorts>,
@@ -3029,6 +3225,7 @@ export function createApi(Z3: Z3Core): Z3HighLevel {
       BitVec,
       Array,
       Set,
+      Datatype,
 
       ////////////////
       // Operations //
diff --git a/src/api/js/src/high-level/types.ts b/src/api/js/src/high-level/types.ts
index 37d9c8f21..3c1ebaa10 100644
--- a/src/api/js/src/high-level/types.ts
+++ b/src/api/js/src/high-level/types.ts
@@ -3,6 +3,8 @@ import {
   Z3_ast_map,
   Z3_ast_vector,
   Z3_context,
+  Z3_constructor,
+  Z3_constructor_list,
   Z3_decl_kind,
   Z3_func_decl,
   Z3_func_entry,
@@ -362,6 +364,8 @@ export interface Context<Name extends string = 'main'> {
   readonly Array: SMTArrayCreation<Name>;
   /** @category Expressions */
   readonly Set: SMTSetCreation<Name>;
+  /** @category Expressions */
+  readonly Datatype: DatatypeCreation<Name>;
 
   ////////////////
   // Operations //
@@ -842,7 +846,8 @@ export interface Sort<Name extends string = 'main'> extends Ast<Name, Z3_sort> {
     | BoolSort['__typename']
     | ArithSort['__typename']
     | BitVecSort['__typename']
-    | SMTArraySort['__typename'];
+    | SMTArraySort['__typename']
+    | DatatypeSort['__typename'];
 
   kind(): Z3_sort_kind;
 
@@ -966,7 +971,8 @@ export interface Expr<Name extends string = 'main', S extends Sort<Name> = AnySo
     | Bool['__typename']
     | Arith['__typename']
     | BitVec['__typename']
-    | SMTArray['__typename'];
+    | SMTArray['__typename']
+    | DatatypeExpr['__typename'];
 
   get sort(): S;
 
@@ -1653,6 +1659,111 @@ export interface SMTSet<Name extends string = 'main', ElemSort extends AnySort<N
   subsetOf(b: SMTSet<Name, ElemSort>): Bool<Name>;
 
 }
+//////////////////////////////////////////
+//
+// Datatypes
+//
+//////////////////////////////////////////
+
+/**
+ * Helper class for declaring Z3 datatypes.
+ * 
+ * Follows the same pattern as Python Z3 API for declaring constructors
+ * before creating the actual datatype sort.
+ * 
+ * @example
+ * ```typescript
+ * const List = new ctx.Datatype('List');
+ * List.declare('cons', ['car', ctx.Int.sort()], ['cdr', List]);
+ * List.declare('nil');
+ * const ListSort = List.create();
+ * ```
+ * 
+ * @category Datatypes
+ */
+export interface Datatype<Name extends string = 'main'> {
+  readonly ctx: Context<Name>;
+  readonly name: string;
+
+  /**
+   * Declare a constructor for this datatype.
+   * 
+   * @param name Constructor name
+   * @param fields Array of [field_name, field_sort] pairs
+   */
+  declare(name: string, ...fields: Array<[string, AnySort<Name> | Datatype<Name>]>): this;
+
+  /**
+   * Create the actual datatype sort from the declared constructors.
+   * For mutually recursive datatypes, use Context.createDatatypes instead.
+   */
+  create(): DatatypeSort<Name>;
+}
+
+/**
+ * @category Datatypes
+ */
+export interface DatatypeCreation<Name extends string> {
+  /**
+   * Create a new datatype declaration helper.
+   */
+  (name: string): Datatype<Name>;
+
+  /**
+   * Create mutually recursive datatypes.
+   * 
+   * @param datatypes Array of Datatype declarations
+   * @returns Array of created DatatypeSort instances
+   */
+  createDatatypes(...datatypes: Datatype<Name>[]): DatatypeSort<Name>[];
+}
+
+/**
+ * A Sort representing an algebraic datatype.
+ * 
+ * After creation, this sort will have constructor, recognizer, and accessor
+ * functions dynamically attached based on the declared constructors.
+ * 
+ * @category Datatypes
+ */
+export interface DatatypeSort<Name extends string = 'main'> extends Sort<Name> {
+  /** @hidden */
+  readonly __typename: 'DatatypeSort';
+
+  /**
+   * Number of constructors in this datatype
+   */
+  numConstructors(): number;
+
+  /**
+   * Get the idx'th constructor function declaration
+   */
+  constructorDecl(idx: number): FuncDecl<Name>;
+
+  /**
+   * Get the idx'th recognizer function declaration
+   */
+  recognizer(idx: number): FuncDecl<Name>;
+
+  /**
+   * Get the accessor function declaration for the idx_a'th field of the idx_c'th constructor
+   */
+  accessor(constructorIdx: number, accessorIdx: number): FuncDecl<Name>;
+
+  cast(other: CoercibleToExpr<Name>): DatatypeExpr<Name>;
+
+  cast(other: DatatypeExpr<Name>): DatatypeExpr<Name>;
+}
+
+/**
+ * Represents expressions of datatype sorts.
+ * 
+ * @category Datatypes  
+ */
+export interface DatatypeExpr<Name extends string = 'main'> extends Expr<Name, DatatypeSort<Name>, Z3_ast> {
+  /** @hidden */
+  readonly __typename: 'DatatypeExpr';
+}
 
 /**
  * Defines the expression type of the body of a quantifier expression
diff --git a/src/smt/smt_parallel.cpp b/src/smt/smt_parallel.cpp
index 5861d7511..2c67532dc 100644
--- a/src/smt/smt_parallel.cpp
+++ b/src/smt/smt_parallel.cpp
@@ -41,50 +41,62 @@ namespace smt {
 namespace smt {
 
     void parallel::worker::run() {
-        ast_translation tr(ctx->m, m);
+        ast_translation g2l(ctx->m, m);
+        ast_translation l2g(m, ctx->m);
         while (m.inc()) {
             vector<expr_ref_vector> cubes;
-            b.get_cubes(tr, cubes);
+            b.get_cubes(g2l, cubes);
             if (cubes.empty())
                 return;
             for (auto& cube : cubes) {
                 if (!m.inc())
                     return; // stop if the main context is cancelled                
                 switch (check_cube(cube)) {
-                case l_undef:
+                case l_undef: {
                     // return unprocessed cubes to the batch manager
                     // add a split literal to the batch manager.
                     // optionally process other cubes and delay sending back unprocessed cubes to batch manager.
-                    b.m_cubes.push_back(cube); // TODO: add access funcs for m_cubes
+                    vector<expr_ref_vector> returned_cubes;
+                    returned_cubes.push_back(cube);
+                    auto split_atoms = get_split_atoms();
+                    b.return_cubes(l2g, returned_cubes, split_atoms);
                     break;
+                }
                 case l_true: {
                     model_ref mdl;
                     ctx->get_model(mdl);
-                    if (mdl) 
-                        ctx->set_model(mdl->translate(tr));
-                    //b.set_sat(tr, *mdl);
+                    b.set_sat(l2g, *mdl);
                     return;
                 }
-                case l_false:
+                case l_false: {
                     // if unsat core only contains (external) assumptions (i.e. all the unsat core are asms), then unsat and return as this does NOT depend on cubes
                     // otherwise, extract lemmas that can be shared (units (and unsat core?)).
                     // share with batch manager.
                     // process next cube.
-                    ctx->m_unsat_core.reset();
-                    for (expr* e : pctx.unsat_core()) // TODO: move this logic to the batch manager since this is per-thread
-                        ctx->m_unsat_core.push_back(tr(e));
+                    auto const& unsat_core = ctx->unsat_core();
+                    // If the unsat core only contains assumptions, 
+                    // unsatisfiability does not depend on the current cube and the entire problem is unsat.
+                    if (any_of(unsat_core, [&](expr* e) { return asms.contains(e); })) {
+                        b.set_unsat(l2g, ctx->unsat_core());
+                        return;
+                    }
+                    // TODO: can share lemmas here, such as new units and not(and(unsat_core)), binary clauses, etc.
+                    // TODO: remember assumptions used in core so that they get used for the final core.
                     break;
                 }
+                }
             }
         }
     }
 
-    parallel::worker::worker(parallel& p, context& _ctx, expr_ref_vector const& _asms): p(p), b(p.m_batch_manager), m_smt_params(_ctx.get_fparams()), asms(m) {
-        ast_translation g2l(_ctx.m, m);
+    parallel::worker::worker(unsigned id, parallel& p, expr_ref_vector const& _asms): id(id), p(p), b(p.m_batch_manager), m_smt_params(p.ctx.get_fparams()), asms(m) {
+        ast_translation g2l(p.ctx.m, m);
         for (auto e : _asms) 
             asms.push_back(g2l(e));        
         m_smt_params.m_preprocess = false;
-        ctx = alloc(context, m, m_smt_params, _ctx.get_params());
+        ctx = alloc(context, m, m_smt_params, p.ctx.get_params());
+        context::copy(p.ctx, *ctx, true);
+        ctx->set_random_seed(id + m_smt_params.m_random_seed);
     }
 
 
@@ -92,10 +104,21 @@ namespace smt {
     // THERE IS AN EDGE CASE: IF ALL THE CUBES ARE UNSAT, BUT DEPEND ON NONEMPTY ASSUMPTIONS, NEED TO TAKE THE UNION OF THESE ASMS WHEN LEARNING FROM UNSAT CORE
     // DON'T CODE THIS CASE YET: WE ARE JUST TESTING WITH EMPTY ASMS FOR NOW (I.E. WE ARE NOT PASSING IN ASMS). THIS DOES NOT APPLY TO THE INTERNAL "LEARNED" UNSAT CORE
     lbool parallel::worker::check_cube(expr_ref_vector const& cube) {
-        for (auto& atom : cube) {
-            asms.push_back(atom);
+        for (auto& atom : cube) 
+            asms.push_back(atom);                
+        lbool r = l_undef;
+        try {
+            r = ctx->check(asms.size(), asms.data());
+        }
+        catch (z3_error& err) {
+            b.set_exception(err.error_code());
+        }
+        catch (z3_exception& ex) {
+            b.set_exception(ex.what());
+        }
+        catch (...) {
+            b.set_exception("unknown exception");
         }
-        lbool r = ctx->check(asms.size(), asms.data());
         asms.shrink(asms.size() - cube.size());
         return r;
     }
@@ -121,19 +144,64 @@ namespace smt {
 
     void parallel::batch_manager::set_sat(ast_translation& l2g, model& m) {
         std::scoped_lock lock(mux);
-        if (m_result == l_true || m_result == l_undef) {
-            m_result = l_true;
+        if (l_true == m_result)
             return;
-        }
         m_result = l_true;
-        for (auto& c : m_cubes) {
-            expr_ref_vector g_cube(l2g.to());
-            for (auto& e : c) {
-                g_cube.push_back(l2g(e));
-            }
-            share_lemma(l2g, mk_and(g_cube));
-        }
+        p.ctx.set_model(m.translate(l2g));
+        cancel_workers();
     }
+
+    void parallel::batch_manager::set_unsat(ast_translation& l2g, expr_ref_vector const& unsat_core) {
+        std::scoped_lock lock(mux);
+        if (l_false == m_result)
+            return;
+        m_result = l_false;
+        expr_ref_vector g_core(l2g.to());
+        for (auto& e : unsat_core) 
+            g_core.push_back(l2g(e));        
+        p.ctx.m_unsat_core.reset();
+        for (expr* e : unsat_core)
+            p.ctx.m_unsat_core.push_back(l2g(e));
+        cancel_workers();
+    }
+
+    void parallel::batch_manager::set_exception(unsigned error_code) {
+        std::scoped_lock lock(mux);
+        if (m_exception_kind != NO_EX)
+            return; // already set
+        m_exception_kind = ERROR_CODE_EX;
+        m_exception_code = error_code;
+        cancel_workers();
+    }
+
+    void parallel::batch_manager::set_exception(std::string const& msg) {
+        std::scoped_lock lock(mux);
+        if (m_exception_kind != NO_EX)
+            return; // already set
+        m_exception_kind = ERROR_MSG_EX;
+        m_exception_msg = msg;
+        cancel_workers();
+    }
+
+    lbool parallel::batch_manager::get_result() const {
+        if (m_exception_kind == ERROR_MSG_EX)
+            throw default_exception(m_exception_msg.c_str());
+        if (m_exception_kind == ERROR_CODE_EX)
+            throw z3_error(m_exception_code);
+        if (m.limit().is_canceled())
+            return l_undef; // the main context was cancelled, so we return undef.
+        return m_result;
+    }
+
+#if 0
+    for (auto& c : m_cubes) {
+        expr_ref_vector g_cube(l2g.to());
+        for (auto& e : c) {
+            g_cube.push_back(l2g(e));
+        }
+        share_lemma(l2g, mk_and(g_cube));
+    }
+#endif
     
     // CALL GET_SPLIT_ATOMS AS ARGUMENT TO RETURN_CUBES
     void parallel::batch_manager::return_cubes(ast_translation& l2g, vector<expr_ref_vector>const& cubes, expr_ref_vector const& split_atoms) {
@@ -172,25 +240,32 @@ namespace smt {
 
         expr_ref_vector top_lits(m);
         for (const auto& node : candidates) {
-            if (ctx->get_assignment(node.key) != l_undef) continue;
+            if (ctx->get_assignment(node.key) != l_undef) 
+                continue;
 
             expr* e = ctx->bool_var2expr(node.key);
-            if (!e) continue;
+            if (!e) 
+                continue;
 
             top_lits.push_back(expr_ref(e, m));
-            if (top_lits.size() >= k) break;
+            if (top_lits.size() >= k) 
+                break;
         }
         return top_lits;
     }
 
     lbool parallel::new_check(expr_ref_vector const& asms) {
         ast_manager& m = ctx.m;
+
+        if (m.has_trace_stream())
+            throw default_exception("trace streams have to be off in parallel mode");
+
         {
             scoped_limits sl(m.limit());
             unsigned num_threads = std::min((unsigned)std::thread::hardware_concurrency(), ctx.get_fparams().m_threads);
             SASSERT(num_threads > 1);
             for (unsigned i = 0; i < num_threads; ++i)
-                m_workers.push_back(alloc(worker, *this, ctx, asms));
+                m_workers.push_back(alloc(worker, i, *this, asms));
                 
             // THIS WILL ALLOW YOU TO CANCEL ALL THE CHILD THREADS
             // within the lexical scope of the code block, creates a data structure that allows you to push children
@@ -210,6 +285,9 @@ namespace smt {
             // Wait for all threads to finish
             for (auto& th : threads)
                 th.join();
+
+            for (auto w : m_workers) 
+                w->collect_statistics(ctx.m_aux_stats);            
         }
         m_workers.clear();
         return m_batch_manager.get_result();        
diff --git a/src/smt/smt_parallel.h b/src/smt/smt_parallel.h
index 9d0a3de3f..e99c95367 100644
--- a/src/smt/smt_parallel.h
+++ b/src/smt/smt_parallel.h
@@ -27,6 +27,12 @@ namespace smt {
         unsigned num_threads;
 
         class batch_manager {        
+
+            enum exception_kind {
+                NO_EX,
+                ERROR_CODE_EX,
+                ERROR_MSG_EX
+            };
             ast_manager& m;
             parallel& p;
             std::mutex mux;
@@ -34,10 +40,19 @@ namespace smt {
             vector<expr_ref_vector> m_cubes;
             lbool m_result = l_false; // want states: init/undef, canceled/exception, sat, unsat
             unsigned m_max_batch_size = 10;
+            exception_kind m_exception_kind = NO_EX;
+            unsigned m_exception_code = 0;
+            std::string m_exception_msg;
+
+            // called from batch manager to cancel other workers if we've reached a verdict
+            void cancel_workers() {
+                for (auto& w : p.m_workers) 
+                    w->cancel();                
+            }
 
         public:
             batch_manager(ast_manager& m, parallel& p) : m(m), p(p), m_split_atoms(m) { m_cubes.push_back(expr_ref_vector(m)); }
-            void set_unsat();
+            void set_unsat(ast_translation& l2g, expr_ref_vector const& unsat_core);
             void set_sat(ast_translation& l2g, model& m);
             void set_exception(std::string const& msg);
             void set_exception(unsigned error_code);
@@ -55,11 +70,11 @@ namespace smt {
             // 
             void return_cubes(ast_translation& l2g, vector<expr_ref_vector>const& cubes, expr_ref_vector const& split_atoms);
             void share_lemma(ast_translation& l2g, expr* lemma);
-            void cancel_workers(); // called from batch manager to cancel other workers if we've reached a verdict
-            lbool get_result() const { return m.limit().is_canceled() ? l_undef : m_result; } 
+            lbool get_result() const;
         };
 
         class worker {
+            unsigned id; // unique identifier for the worker
             parallel& p;
             batch_manager& b;
             ast_manager m;
@@ -71,7 +86,7 @@ namespace smt {
             void share_units();
             lbool check_cube(expr_ref_vector const& cube);
         public:
-            worker(parallel& p, context& _ctx, expr_ref_vector const& _asms);
+            worker(unsigned id, parallel& p, expr_ref_vector const& _asms);
             void run();
             expr_ref_vector get_split_atoms();
             void cancel() {