Make certificate checker export return statements

coq/CertificateChecker.v

@@ -9,7 +9,7 @@ Require Import Daisy.Infra.RealSimps Daisy.Infra.RationalSimps Daisy.Infra.RealR
 Require Import Daisy.IntervalValidation Daisy.ErrorValidation Daisy.Environments.
 
 Require Export Coq.QArith.QArith.
-Require Export Daisy.Infra.ExpressionAbbrevs.
+Require Export Daisy.Infra.ExpressionAbbrevs Daisy.Commands.
 
 (** Certificate checking function **)
 Definition CertificateChecker (e:exp Q) (absenv:analysisResult) (P:precond) :=
@@ -104,4 +104,4 @@ Proof.
   - intros v v_in_empty.
     rewrite NatSet.mem_spec in v_in_empty.
     inversion v_in_empty.
-Qed.
\ No newline at end of file
+Qed.