Fix some stuff as explained by Magnus

hol4/ErrorValidationScript.sml

@@ -71,12 +71,13 @@ val err_always_positive = store_thm ("err_always_positive",
 val validErrorboundCorrectVariable = store_thm ("validErrorboundCorrectVariable",
   ``!(ParamEnv:env) (v:num)
      (nR nF err nlo nhi:real) (P:precond) VarEnv1 absenv VarEnv2.
-      approxEnv VarEnv1 absenv VarEnv2 ==>
+      approxEnv VarEnv1 absenv VarEnv2 /\
       eval_exp 0 VarEnv1 ParamEnv P (Var v) nR /\
       eval_exp machineEpsilon VarEnv2 ParamEnv P (Var v) nF /\
       validErrorbound (Var v) absenv /\
       (absenv (Var v) = ((nlo, nhi),err)) ==>
       abs (nR - nF) <= err``,
+  once_rewrite_tac [GSYM AND_IMP_INTRO] \\
   gen_tac \\ gen_tac \\ gen_tac \\ gen_tac \\ gen_tac \\ gen_tac \\
   gen_tac \\ gen_tac \\
   ho_match_mp_tac approxEnv_ind \\
@@ -132,11 +133,11 @@ val validErrorboundCorrectParam = store_thm ("validErrorboundCorrectParam",
          MEM v1 (freeVars ((Param v):real exp)) ==>
          isSupersetInterval (P v1) (FST (absenv (Param v1)))) /\
       (absenv (Param v) = ((nlo,nhi),e)) ==>
-      (abs (nR - nF)) <= e``
+      (abs (nR - nF)) <= e``,
   once_rewrite_tac [validErrorbound_def] \\
   rpt strip_tac \\ fs[] \\
   qpat_x_assum `absenv _ = _` (fn thm => rule_assum_tac (fn thm2 => REWRITE_RULE [thm] thm2)) \\
-  inversion `eval_exp 0 _ _ _ _ _` eval_exp_cases \\ rveq \\
+  inversion `eval_exp 0 _ _ _ _ _ ` eval_exp_cases \\ rveq \\
   simp [delta_0_deterministic] \\
   inversion `eval_exp _ _ _ _ _ _` eval_exp_cases \\ rveq \\
   simp [perturb_def] \\