+typedef struct {
+ BDD bdd;
+ variables vars;
+} state;
+
+typedef struct trans {
+ BDD bdd;
+ variables varset;
+ struct trans *next_rel;
+} trans_t;
+
+typedef struct {
+ trans_t *rell;
+ trans_t *relu;
+ trans_t *relr;
+ trans_t *reld;
+} rels;
+
+typedef enum { LEFT, UP, RIGHT, DOWN } direction;
+
+state *encode_screen(sokoban_screen *screen);
+
+rels *encode_rel(sokoban_screen *screen);
+
+int test_trans(state *s, trans_t *t);
+
+int test_relprod();