; COMMAND-LINE: --strings-exp --no-check-models (set-logic ALL) (set-info :status sat) (declare-datatypes ((a 0)) (((b)))) (define-fun v () (Seq Bool) (as seq.empty (Seq Bool))) (declare-fun e () (Seq a)) (define-fun w () Int (seq.len e)) (define-fun x () (Seq a) (seq.extract e 1 (- w 1))) (define-fun i () (Seq a) (seq.extract x 1 (- (seq.len x) 1))) (define-fun y () (Seq Bool) (ite (= 0 (seq.len i)) v (seq.unit true))) (define-fun m () (Seq Bool) (seq.++ (seq.unit false) y)) (define-fun n () (Seq Bool) (ite (= 0 (seq.len x)) v m)) (define-fun o () (Seq Bool) (seq.++ (seq.unit false) n)) (define-fun p () (Seq Bool) (ite (= 0 w) v o)) (define-fun s () (Seq Bool) (seq.extract p 1 (- (seq.len p) 1))) (define-fun u () (Seq Bool) (seq.extract s 1 (- (seq.len s) 1))) (assert (not (seq.nth u 0))) (check-sat)