(* increase clocks of states   *) 


  (*  Reachable states from "Sini" with transitions "tr"  *)

  Inductive RState (Sini : S) : S -> Prop :=
    | rsIni : RState Sini Sini
    | rsNextTick :
        forall s : S,
        RState Sini s -> inv (inc s tick) -> RState Sini (inc s tick)
    | rsNextDisc :
        forall (s1 s2 : S) (l : Label),
        RState Sini s1 -> tr s1 l s2 -> inv s2 -> RState Sini s2.(* increase clocks of states   *) 


  (*  Reachable states from "Sini" with transitions "tr"  *)

  Inductive RState (Sini : S) : S -> Prop :=
    | rsIni : RState Sini Sini
    | rsNextTick :
        forall s : S,
        RState Sini s -> inv (inc s tick) -> RState Sini (inc s tick)
    | rsNextDisc :
        forall (s1 s2 : S) (l : Label),
        RState Sini s1 -> tr s1 l s2 -> inv s2 -> RState Sini s2.(* increase clocks of states   *) 


  (*  Reachable states from "Sini" with transitions "tr"  *)

  Inductive RState (Sini : S) : S -> Prop :=
    | rsIni : RState Sini Sini
    | rsNextTick :
        forall s : S,
        RState Sini s -> inv (inc s tick) -> RState Sini (inc s tick)
    | rsNextDisc :
        forall (s1 s2 : S) (l : Label),
        RState Sini s1 -> tr s1 l s2 -> inv s2 -> RState Sini s2.(* increase clocks of states   *) 


  (*  Reachable states from "Sini" with transitions "tr"  *)

  Inductive RState (Sini : S) : S -> Prop :=
    | rsIni : RState Sini Sini
    | rsNextTick :
        forall s : S,
        RState Sini s -> inv (inc s tick) -> RState Sini (inc s tick)
    | rsNextDisc :
        forall (s1 s2 : S) (l : Label),
        RState Sini s1 -> tr s1 l s2 -> inv s2 -> RState Sini s2.(*  Reachable states from "Sini" with transitions "tr" in time units  *)

  Inductive RState_T (Sini : S) : S -> Instant -> Prop :=
    | rsIni_T : RState_T Sini Sini time0
    | rsNextTick_T :
        forall (s : S) (t : Instant),
        RState_T Sini s t ->
        inv (inc s tick) -> RState_T Sini (inc s tick) (Inc t)
    | rsNextDisc_T :
        forall (s1 s2 : S) (l : Label) (t : Instant),
        RState_T Sini s1 t -> tr s1 l s2 -> inv s2 -> RState_T Sini s2 t.(*  Reachable states from "Sini" with transitions "tr" in time units  *)

  Inductive RState_T (Sini : S) : S -> Instant -> Prop :=
    | rsIni_T : RState_T Sini Sini time0
    | rsNextTick_T :
        forall (s : S) (t : Instant),
        RState_T Sini s t ->
        inv (inc s tick) -> RState_T Sini (inc s tick) (Inc t)
    | rsNextDisc_T :
        forall (s1 s2 : S) (l : Label) (t : Instant),
        RState_T Sini s1 t -> tr s1 l s2 -> inv s2 -> RState_T Sini s2 t.(*  Reachable states from "Sini" with transitions "tr" in time units  *)

  Inductive RState_T (Sini : S) : S -> Instant -> Prop :=
    | rsIni_T : RState_T Sini Sini time0
    | rsNextTick_T :
        forall (s : S) (t : Instant),
        RState_T Sini s t ->
        inv (inc s tick) -> RState_T Sini (inc s tick) (Inc t)
    | rsNextDisc_T :
        forall (s1 s2 : S) (l : Label) (t : Instant),
        RState_T Sini s1 t -> tr s1 l s2 -> inv s2 -> RState_T Sini s2 t.(*  Reachable states from "Sini" with transitions "tr" in time units  *)

  Inductive RState_T (Sini : S) : S -> Instant -> Prop :=
    | rsIni_T : RState_T Sini Sini time0
    | rsNextTick_T :
        forall (s : S) (t : Instant),
        RState_T Sini s t ->
        inv (inc s tick) -> RState_T Sini (inc s tick) (Inc t)
    | rsNextDisc_T :
        forall (s1 s2 : S) (l : Label) (t : Instant),
        RState_T Sini s1 t -> tr s1 l s2 -> inv s2 -> RState_T Sini s2 t.(**************************************************************************)
  (*                       Invariants and Reachability                      *)
  (**************************************************************************)  

  (*  Init => FA[] P  *)

  Definition ForAll (Sini : S) (P : S -> Prop) :=
    forall s : S, RState Sini s -> P s.(*  Init => FA[](bound t) P  *)

  Definition ForAll_T (Sini : S) (P : S -> Prop) (bound : Instant -> Prop) :=
    forall (s : S) (t : Instant), bound t -> RState_T Sini s t -> P s.(*  Init => EX<> P  *)

  Inductive Exists (Sini : S) (P : S -> Prop) : Prop :=
      exists_ : forall s : S, RState Sini s -> P s -> Exists Sini P.(*  Init => EX<> P  *)

  Inductive Exists (Sini : S) (P : S -> Prop) : Prop :=
      exists_ : forall s : S, RState Sini s -> P s -> Exists Sini P.(*  Init => EX<>(bound t) P  *)

  Inductive Exists_T (Sini : S) (P : S -> Prop) (bound : Instant -> Prop) :
  Prop :=
      exists_T :
        forall (s : S) (t : Instant),
        bound t -> RState_T Sini s t -> P s -> Exists_T Sini P bound.(*  Init => EX<>(bound t) P  *)

  Inductive Exists_T (Sini : S) (P : S -> Prop) (bound : Instant -> Prop) :
  Prop :=
      exists_T :
        forall (s : S) (t : Instant),
        bound t -> RState_T Sini s t -> P s -> Exists_T Sini P bound.

Theorem StepsEX : forall (s1 s2 : S) (P : S -> Prop), RState s1 s2 -> Exists s2 P -> Exists s1 P.