File Alloc.ML (Isabelle2005: October 2005)

# File Alloc.ML

    (*  Title:      HOL/UNITY/Alloc
        ID:         $Id: Alloc.ML,v 1.3 2005/02/13 16:20:11 skalberg Exp $
        Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
        Copyright   1998  University of Cambridge

    Specification of Chandy and Charpentier's Allocator
    *)

    (*Perhaps equalities.ML shouldn't add this in the first place!*)
    Delsimps [image_Collect];

    AddIs    [impOfSubs subset_preserves_o];
    Addsimps [impOfSubs subset_preserves_o];
    Addsimps [funPair_o_distrib];
    Addsimps [Always_INT_distrib];
    Delsimps [o_apply];

    (*Eliminate the "o" operator*)
    val o_simp = simplify (simpset() addsimps [o_def]);

    (*For rewriting of specifications related by "guarantees"*)
    Addsimps [rename_image_constrains, rename_image_stable,
    	  rename_image_increasing, rename_image_invariant,
    	  rename_image_Constrains, rename_image_Stable,
    	  rename_image_Increasing, rename_image_Always,
    	  rename_image_leadsTo, rename_image_LeadsTo,
    	  rename_preserves, rename_image_preserves, lift_image_preserves,
    	  bij_image_INT, bij_is_inj RS image_Int, bij_image_Collect_eq];

    (*Splits up conjunctions & intersections: like CONJUNCTS in the HOL system*)
    fun list_of_Int th =
        (list_of_Int (th RS conjunct1) @ list_of_Int (th RS conjunct2))
        handle THM _ => (list_of_Int (th RS IntD1) @ list_of_Int (th RS IntD2))
        handle THM _ => (list_of_Int (th RS INT_D))
        handle THM _ => (list_of_Int (th RS bspec))
        handle THM _ => [th];

    (*Used just once, for Alloc_Increasing*)
    val lessThanBspec = lessThan_iff RS iffD2 RSN (2, bspec);
    fun normalize th =
         normalize (th RS spec
    		handle THM _ => th RS lessThanBspec
    		handle THM _ => th RS bspec
    		handle THM _ => th RS (guarantees_INT_right_iff RS iffD1))
         handle THM _ => th;

    (*** bijectivity of sysOfAlloc [MUST BE AUTOMATED] ***)

    val record_auto_tac =
        auto_tac (claset() addIs [ext] addSWrapper record_split_wrapper,
    	      simpset() addsimps [sysOfAlloc_def, sysOfClient_def,
    				  client_map_def, non_dummy_def, funPair_def,
    				  o_apply, Let_def]);

    Goalw [sysOfAlloc_def, Let_def] "inj sysOfAlloc";
    by (rtac injI 1);
    by record_auto_tac;
    qed "inj_sysOfAlloc";
    AddIffs [inj_sysOfAlloc];

    (*We need the inverse; also having it simplifies the proof of surjectivity*)
    Goal "!!s. inv sysOfAlloc s = \
    \            (| allocGiv = allocGiv s,   \
    \               allocAsk = allocAsk s,   \
    \               allocRel = allocRel s,   \
    \               allocState_d.dummy = (client s, dummy s) |)";
    by (rtac (inj_sysOfAlloc RS inv_f_eq) 1);
    by record_auto_tac;
    qed "inv_sysOfAlloc_eq";
    Addsimps [inv_sysOfAlloc_eq];

    Goal "surj sysOfAlloc";
    by (simp_tac (simpset() addsimps [surj_iff, expand_fun_eq, o_apply]) 1);
    by record_auto_tac;
    qed "surj_sysOfAlloc";
    AddIffs [surj_sysOfAlloc];

    Goal "bij sysOfAlloc";
    by (blast_tac (claset() addIs [bijI]) 1);
    qed "bij_sysOfAlloc";
    AddIffs [bij_sysOfAlloc];

    (*** bijectivity of sysOfClient ***)

    Goalw [sysOfClient_def] "inj sysOfClient";
    by (rtac injI 1);
    by record_auto_tac;
    qed "inj_sysOfClient";
    AddIffs [inj_sysOfClient];

    Goal "!!s. inv sysOfClient s = \
    \            (client s, \
    \             (| allocGiv = allocGiv s, \
    \                allocAsk = allocAsk s, \
    \                allocRel = allocRel s, \
    \                allocState_d.dummy = systemState.dummy s|) )";
    by (rtac (inj_sysOfClient RS inv_f_eq) 1);
    by record_auto_tac;
    qed "inv_sysOfClient_eq";
    Addsimps [inv_sysOfClient_eq];

    Goal "surj sysOfClient";
    by (simp_tac (simpset() addsimps [surj_iff, expand_fun_eq, o_apply]) 1);
    by record_auto_tac;
    qed "surj_sysOfClient";
    AddIffs [surj_sysOfClient];

    Goal "bij sysOfClient";
    by (blast_tac (claset() addIs [bijI]) 1);
    qed "bij_sysOfClient";
    AddIffs [bij_sysOfClient];

    (*** bijectivity of client_map ***)

    Goalw [inj_on_def] "inj client_map";
    by record_auto_tac;
    qed "inj_client_map";
    AddIffs [inj_client_map];

    Goal "!!s. inv client_map s = \
    \            (%(x,y).(|giv = giv x, ask = ask x, rel = rel x, \
    \                      clientState_d.dummy = y|)) s";
    by (rtac (inj_client_map RS inv_f_eq) 1);
    by record_auto_tac;
    qed "inv_client_map_eq";
    Addsimps [inv_client_map_eq];

    Goal "surj client_map";
    by (simp_tac (simpset() addsimps [surj_iff, expand_fun_eq, o_apply]) 1);
    by record_auto_tac;
    qed "surj_client_map";
    AddIffs [surj_client_map];

    Goal "bij client_map";
    by (blast_tac (claset() addIs [bijI]) 1);
    qed "bij_client_map";
    AddIffs [bij_client_map];

    (** o-simprules for client_map **)

    Goalw [client_map_def] "fst o client_map = non_dummy";
    by (rtac fst_o_funPair 1);
    qed "fst_o_client_map";
    Addsimps (make_o_equivs fst_o_client_map);

    Goalw [client_map_def] "snd o client_map = clientState_d.dummy";
    by (rtac snd_o_funPair 1);
    qed "snd_o_client_map";
    Addsimps (make_o_equivs snd_o_client_map);

    (** o-simprules for sysOfAlloc [MUST BE AUTOMATED] **)

    Goal "client o sysOfAlloc = fst o allocState_d.dummy ";
    by record_auto_tac;
    qed "client_o_sysOfAlloc";
    Addsimps (make_o_equivs client_o_sysOfAlloc);

    Goal "allocGiv o sysOfAlloc = allocGiv";
    by record_auto_tac;
    qed "allocGiv_o_sysOfAlloc_eq";
    Addsimps (make_o_equivs allocGiv_o_sysOfAlloc_eq);

    Goal "allocAsk o sysOfAlloc = allocAsk";
    by record_auto_tac;
    qed "allocAsk_o_sysOfAlloc_eq";
    Addsimps (make_o_equivs allocAsk_o_sysOfAlloc_eq);

    Goal "allocRel o sysOfAlloc = allocRel";
    by record_auto_tac;
    qed "allocRel_o_sysOfAlloc_eq";
    Addsimps (make_o_equivs allocRel_o_sysOfAlloc_eq);

    (** o-simprules for sysOfClient [MUST BE AUTOMATED] **)

    Goal "client o sysOfClient = fst";
    by record_auto_tac;
    qed "client_o_sysOfClient";
    Addsimps (make_o_equivs client_o_sysOfClient);

    Goal "allocGiv o sysOfClient = allocGiv o snd ";
    by record_auto_tac;
    qed "allocGiv_o_sysOfClient_eq";
    Addsimps (make_o_equivs allocGiv_o_sysOfClient_eq);

    Goal "allocAsk o sysOfClient = allocAsk o snd ";
    by record_auto_tac;
    qed "allocAsk_o_sysOfClient_eq";
    Addsimps (make_o_equivs allocAsk_o_sysOfClient_eq);

    Goal "allocRel o sysOfClient = allocRel o snd ";
    by record_auto_tac;
    qed "allocRel_o_sysOfClient_eq";
    Addsimps (make_o_equivs allocRel_o_sysOfClient_eq);

    Goal "allocGiv o inv sysOfAlloc = allocGiv";
    by (simp_tac (simpset() addsimps [o_def]) 1);
    qed "allocGiv_o_inv_sysOfAlloc_eq";
    Addsimps (make_o_equivs allocGiv_o_inv_sysOfAlloc_eq);

    Goal "allocAsk o inv sysOfAlloc = allocAsk";
    by (simp_tac (simpset() addsimps [o_def]) 1);
    qed "allocAsk_o_inv_sysOfAlloc_eq";
    Addsimps (make_o_equivs allocAsk_o_inv_sysOfAlloc_eq);

    Goal "allocRel o inv sysOfAlloc = allocRel";
    by (simp_tac (simpset() addsimps [o_def]) 1);
    qed "allocRel_o_inv_sysOfAlloc_eq";
    Addsimps (make_o_equivs allocRel_o_inv_sysOfAlloc_eq);

    Goal "(rel o inv client_map o drop_map i o inv sysOfClient) = \
    \     rel o sub i o client";
    by (simp_tac (simpset() addsimps [o_def, drop_map_def]) 1);
    qed "rel_inv_client_map_drop_map";
    Addsimps (make_o_equivs rel_inv_client_map_drop_map);

    Goal "(ask o inv client_map o drop_map i o inv sysOfClient) = \
    \     ask o sub i o client";
    by (simp_tac (simpset() addsimps [o_def, drop_map_def]) 1);
    qed "ask_inv_client_map_drop_map";
    Addsimps (make_o_equivs ask_inv_client_map_drop_map);

    (**
    Open_locale "System";

    val Alloc = thm "Alloc";
    val Client = thm "Client";
    val Network = thm "Network";
    val System_def = thm "System_def";

    CANNOT use bind_thm: it puts the theorem into standard form, in effect
      exporting it from the locale
    **)

    AddIffs [finite_lessThan];

    (*Client : <unfolded specification> *)
    val client_spec_simps =
        [client_spec_def, client_increasing_def, client_bounded_def,
         client_progress_def, client_allowed_acts_def, client_preserves_def,
         guarantees_Int_right];

    val [Client_Increasing_ask, Client_Increasing_rel,
         Client_Bounded, Client_Progress, Client_AllowedActs,
         Client_preserves_giv, Client_preserves_dummy] =
            Client |> simplify (simpset() addsimps client_spec_simps)
                   |> list_of_Int;

    AddIffs [Client_Increasing_ask, Client_Increasing_rel, Client_Bounded,
    	 Client_preserves_giv, Client_preserves_dummy];

    (*Network : <unfolded specification> *)
    val network_spec_simps =
        [network_spec_def, network_ask_def, network_giv_def,
         network_rel_def, network_allowed_acts_def, network_preserves_def,
         ball_conj_distrib];

    val [Network_Ask, Network_Giv, Network_Rel, Network_AllowedActs,
         Network_preserves_allocGiv, Network_preserves_rel,
         Network_preserves_ask]  =
            Network |> simplify (simpset() addsimps network_spec_simps)
                    |> list_of_Int;

    AddIffs  [Network_preserves_allocGiv];

    Addsimps [Network_preserves_rel, Network_preserves_ask];
    Addsimps [o_simp Network_preserves_rel, o_simp Network_preserves_ask];

    (*Alloc : <unfolded specification> *)
    val alloc_spec_simps =
        [alloc_spec_def, alloc_increasing_def, alloc_safety_def,
    		  alloc_progress_def, alloc_allowed_acts_def,
                      alloc_preserves_def];

    val [Alloc_Increasing_0, Alloc_Safety, Alloc_Progress, Alloc_AllowedActs,
         Alloc_preserves_allocRel, Alloc_preserves_allocAsk,
         Alloc_preserves_dummy] =
            Alloc |> simplify (simpset() addsimps alloc_spec_simps)
                  |> list_of_Int;

    (*Strip off the INT in the guarantees postcondition*)
    val Alloc_Increasing = normalize Alloc_Increasing_0;

    AddIffs [Alloc_preserves_allocRel, Alloc_preserves_allocAsk,
             Alloc_preserves_dummy];

    (** Components lemmas [MUST BE AUTOMATED] **)

    Goal "Network Join \
    \     ((rename sysOfClient \
    \       (plam x: (lessThan Nclients). rename client_map Client)) Join \
    \      rename sysOfAlloc Alloc) \
    \     = System";
    by (simp_tac (simpset() addsimps System_def::Join_ac) 1);
    qed "Network_component_System";

    Goal "(rename sysOfClient \
    \      (plam x: (lessThan Nclients). rename client_map Client)) Join \
    \     (Network Join rename sysOfAlloc Alloc)  =  System";
    by (simp_tac (simpset() addsimps System_def::Join_ac) 1);
    qed "Client_component_System";

    Goal "rename sysOfAlloc Alloc Join \
    \      ((rename sysOfClient (plam x: (lessThan Nclients). rename client_map Client)) Join \
    \       Network)  =  System";
    by (simp_tac (simpset() addsimps System_def::Join_ac) 1);
    qed "Alloc_component_System";

    AddIffs [Client_component_System, Network_component_System,
    	 Alloc_component_System];

    (** These preservation laws should be generated automatically **)

    Goal "Allowed Client = preserves rel Int preserves ask";
    by (auto_tac (claset(),
                  simpset() addsimps [Allowed_def, Client_AllowedActs,
                                      safety_prop_Acts_iff]));
    qed "Client_Allowed";
    Addsimps [Client_Allowed];

    Goal "Allowed Network =        \
    \       preserves allocRel Int \
    \       (INT i: lessThan Nclients. preserves(giv o sub i o client))";
    by (auto_tac (claset(),
                  simpset() addsimps [Allowed_def, Network_AllowedActs,
                                      safety_prop_Acts_iff]));
    qed "Network_Allowed";
    Addsimps [Network_Allowed];

    Goal "Allowed Alloc = preserves allocGiv";
    by (auto_tac (claset(),
                  simpset() addsimps [Allowed_def, Alloc_AllowedActs,
                                      safety_prop_Acts_iff]));
    qed "Alloc_Allowed";
    Addsimps [Alloc_Allowed];

    Goal "OK I (%i. lift i (rename client_map Client))";
    by (rtac OK_lift_I 1);
    by Auto_tac;
    by (dres_inst_tac [("w1", "rel")] (impOfSubs subset_preserves_o) 1);
    by (dres_inst_tac [("w1", "ask")] (impOfSubs subset_preserves_o) 2);
    by (auto_tac (claset(), simpset() addsimps [o_def, split_def]));
    qed "OK_lift_rename_Client";
    Addsimps [OK_lift_rename_Client]; (*needed in rename_client_map_tac*

    (*The proofs of rename_Client_Increasing, rename_Client_Bounded and
      rename_Client_Progress are similar.  All require copying out the original
      Client property.  A forward proof can be constructed as follows:

      Client_Increasing_ask RS
          (bij_client_map RS rename_rename_guarantees_eq RS iffD2)
      RS (lift_lift_guarantees_eq RS iffD2)
      RS guarantees_PLam_I
      RS (bij_sysOfClient RS rename_rename_guarantees_eq RS iffD2)
      |> simplify (simpset() addsimps [lift_image_eq_rename, o_def, split_def,
    				   surj_rename RS surj_range]);

    However, the "preserves" property remains to be discharged, and the unfolding
    of "o" and "sub" complicates subsequent reasoning.

    The following tactic works for all three proofs, though it certainly looks
    ad-hoc!
    *)
    val rename_client_map_tac =
      EVERY [
        simp_tac (simpset() addsimps [rename_guarantees_eq_rename_inv]) 1,
        rtac guarantees_PLam_I 1,
        assume_tac 2,
    	 (*preserves: routine reasoning*)
        asm_simp_tac (simpset() addsimps [lift_preserves_sub]) 2,
    	 (*the guarantee for  "lift i (rename client_map Client)" *)
        asm_simp_tac
    	(simpset() addsimps [lift_guarantees_eq_lift_inv,
    			     rename_guarantees_eq_rename_inv,
    			     bij_imp_bij_inv, surj_rename RS surj_range,
    			     inv_inv_eq]) 1,
        asm_simp_tac
            (simpset() addsimps [o_def, non_dummy_def, guarantees_Int_right]) 1];

    (*Lifting Client_Increasing to systemState*)
    Goal "i : I \
    \     ==> rename sysOfClient (plam x: I. rename client_map Client) : \
    \           UNIV  guarantees  \
    \           Increasing (ask o sub i o client) Int \
    \           Increasing (rel o sub i o client)";
    by rename_client_map_tac;
    qed "rename_Client_Increasing";

    Goal "[| F : preserves w; i ~= j |] \
    \     ==> F : preserves (sub i o fst o lift_map j o funPair v w)";
    by (auto_tac (claset(),
           simpset() addsimps [lift_map_def, split_def, linorder_neq_iff, o_def]));
    by (ALLGOALS (dtac (impOfSubs subset_preserves_o)));
    by (auto_tac (claset(), simpset() addsimps [o_def]));
    qed "preserves_sub_fst_lift_map";

    Goal "[| i < Nclients; j < Nclients |] \
    \     ==> Client : preserves (giv o sub i o fst o lift_map j o client_map)";
    by (case_tac "i=j" 1);
    by (asm_full_simp_tac (simpset() addsimps [o_def, non_dummy_def]) 1);
    by (dtac (Client_preserves_dummy RS preserves_sub_fst_lift_map) 1);
    by (ALLGOALS (dtac (impOfSubs subset_preserves_o)));
    by (asm_full_simp_tac (simpset() addsimps [o_def, client_map_def]) 1);
    qed "client_preserves_giv_oo_client_map";

    Goal "rename sysOfClient (plam x: lessThan Nclients. rename client_map Client)\
    \     ok Network";
    by (auto_tac (claset(), simpset() addsimps [ok_iff_Allowed,
            client_preserves_giv_oo_client_map]));
    qed "rename_sysOfClient_ok_Network";

    Goal "rename sysOfClient (plam x: lessThan Nclients. rename client_map Client)\
    \     ok rename sysOfAlloc Alloc";
    by (simp_tac (simpset() addsimps [ok_iff_Allowed]) 1);
    qed "rename_sysOfClient_ok_Alloc";

    Goal "rename sysOfAlloc Alloc ok Network";
    by (simp_tac (simpset() addsimps [ok_iff_Allowed]) 1);
    qed "rename_sysOfAlloc_ok_Network";

    AddIffs [rename_sysOfClient_ok_Network, rename_sysOfClient_ok_Alloc,
             rename_sysOfAlloc_ok_Network];

    (*The "ok" laws, re-oriented*)
    AddIffs [rename_sysOfClient_ok_Network RS ok_sym,
             rename_sysOfClient_ok_Alloc RS ok_sym,
             rename_sysOfAlloc_ok_Network RS ok_sym];

    Goal "i < Nclients \
    \     ==> System : Increasing (ask o sub i o client) Int \
    \                  Increasing (rel o sub i o client)";
    by (rtac ([rename_Client_Increasing,
    	   Client_component_System] MRS component_guaranteesD) 1);
    by Auto_tac;
    qed "System_Increasing";

    bind_thm ("rename_guarantees_sysOfAlloc_I",
    	  bij_sysOfAlloc RS rename_rename_guarantees_eq RS iffD2);

    (*Lifting Alloc_Increasing up to the level of systemState*)
    val rename_Alloc_Increasing =
        Alloc_Increasing RS rename_guarantees_sysOfAlloc_I
         |> simplify (simpset() addsimps [surj_rename RS surj_range, o_def]);

    Goalw [System_def]
         "i < Nclients ==> System : Increasing (sub i o allocGiv)";
    by (simp_tac (simpset() addsimps [o_def]) 1);
    by (rtac (rename_Alloc_Increasing RS guarantees_Join_I1 RS guaranteesD) 1);
    by Auto_tac;
    qed "System_Increasing_allocGiv";

    AddSIs (list_of_Int System_Increasing);

    (** Follows consequences.
        The "Always (INT ...) formulation expresses the general safety property
        and allows it to be combined using Always_Int_rule below. **)

    Goal
      "i < Nclients ==> System : ((sub i o allocRel) Fols (rel o sub i o client))";
    by (auto_tac (claset() addSIs [Network_Rel RS component_guaranteesD],
    	      simpset()));
    qed "System_Follows_rel";

    Goal
      "i < Nclients ==> System : ((sub i o allocAsk) Fols (ask o sub i o client))";
    by (auto_tac (claset() addSIs [Network_Ask RS component_guaranteesD],
    	      simpset()));
    qed "System_Follows_ask";

    Goal
      "i < Nclients ==> System : (giv o sub i o client) Fols (sub i o allocGiv)";
    by (auto_tac (claset() addSIs [Network_Giv RS component_guaranteesD,
    		 rename_Alloc_Increasing RS component_guaranteesD],
    	      simpset()));
    by (ALLGOALS (simp_tac (simpset() addsimps [o_def, non_dummy_def])));
    by (auto_tac
        (claset() addSIs [rename_Alloc_Increasing RS component_guaranteesD],
         simpset()));
    qed "System_Follows_allocGiv";

    Goal "System : Always (INT i: lessThan Nclients. \
    \                      {s. (giv o sub i o client) s <= (sub i o allocGiv) s})";
    by Auto_tac;
    by (etac (System_Follows_allocGiv RS Follows_Bounded) 1);
    qed "Always_giv_le_allocGiv";

    Goal "System : Always (INT i: lessThan Nclients. \
    \                      {s. (sub i o allocAsk) s <= (ask o sub i o client) s})";
    by Auto_tac;
    by (etac (System_Follows_ask RS Follows_Bounded) 1);
    qed "Always_allocAsk_le_ask";

    Goal "System : Always (INT i: lessThan Nclients. \
    \                      {s. (sub i o allocRel) s <= (rel o sub i o client) s})";
    by (auto_tac (claset() addSIs [Follows_Bounded, System_Follows_rel],
    	      simpset()));
    qed "Always_allocRel_le_rel";

    (*** Proof of the safety property (1) ***)

    (*safety (1), step 1 is System_Follows_rel*)

    (*safety (1), step 2*)
    (* i < Nclients ==> System : Increasing (sub i o allocRel) *)
    bind_thm ("System_Increasing_allocRel",
              System_Follows_rel RS Follows_Increasing1);

    (*Lifting Alloc_safety up to the level of systemState.
      Simplififying with o_def gets rid of the translations but it unfortunately
      gets rid of the other "o"s too.*)
    val rename_Alloc_Safety =
        Alloc_Safety RS rename_guarantees_sysOfAlloc_I
         |> simplify (simpset() addsimps [o_def]);

    (*safety (1), step 3*)
    Goal
      "System : Always {s. (∑i: lessThan Nclients. (tokens o sub i o allocGiv) s) \
    \           <= NbT + (∑i: lessThan Nclients. (tokens o sub i o allocRel) s)}";
    by (simp_tac (simpset() addsimps [o_apply]) 1);
    by (rtac (rename_Alloc_Safety RS component_guaranteesD) 1);
    by (auto_tac (claset(),
                  simpset() addsimps [o_simp System_Increasing_allocRel]));
    qed "System_sum_bounded";

    (** Follows reasoning **)

    Goal "System : Always (INT i: lessThan Nclients. \
    \                         {s. (tokens o giv o sub i o client) s \
    \                          <= (tokens o sub i o allocGiv) s})";
    by (rtac (Always_giv_le_allocGiv RS Always_weaken) 1);
    by (auto_tac (claset() addIs [tokens_mono_prefix],
    	      simpset() addsimps [o_apply]));
    qed "Always_tokens_giv_le_allocGiv";

    Goal "System : Always (INT i: lessThan Nclients. \
    \                         {s. (tokens o sub i o allocRel) s \
    \                          <= (tokens o rel o sub i o client) s})";
    by (rtac (Always_allocRel_le_rel RS Always_weaken) 1);
    by (auto_tac (claset() addIs [tokens_mono_prefix],
    	      simpset() addsimps [o_apply]));
    qed "Always_tokens_allocRel_le_rel";

    (*safety (1), step 4 (final result!) *)
    Goalw [system_safety_def] "System : system_safety";
    by (rtac (Always_Int_rule [System_sum_bounded, Always_tokens_giv_le_allocGiv,
    			   Always_tokens_allocRel_le_rel] RS Always_weaken) 1);
    by Auto_tac;
    by (rtac (setsum_fun_mono RS order_trans) 1);
    by (dtac order_trans 2);
    by (rtac ([order_refl, setsum_fun_mono] MRS add_le_mono) 2);
    by (assume_tac 3);
    by Auto_tac;
    qed "System_safety";

    (*** Proof of the progress property (2) ***)

    (*progress (2), step 1 is System_Follows_ask and System_Follows_rel*)

    (*progress (2), step 2; see also System_Increasing_allocRel*)
    (* i < Nclients ==> System : Increasing (sub i o allocAsk) *)
    bind_thm ("System_Increasing_allocAsk",
              System_Follows_ask RS Follows_Increasing1);

    (*progress (2), step 3: lifting "Client_Bounded" to systemState*)
    Goal "i : I \
    \   ==> rename sysOfClient (plam x: I. rename client_map Client) : \
    \         UNIV  guarantees  \
    \         Always {s. ALL elt : set ((ask o sub i o client) s). elt <= NbT}";
    by rename_client_map_tac;
    qed "rename_Client_Bounded";

    Goal "i < Nclients \
    \     ==> System : Always \
    \                   {s. ALL elt : set ((ask o sub i o client) s). elt <= NbT}";
    by (rtac ([rename_Client_Bounded,
    	   Client_component_System] MRS component_guaranteesD) 1);
    by Auto_tac;
    qed "System_Bounded_ask";

    Goal "{x. ALL y. P y --> Q x y} = (INT y: {y. P y}. {x. Q x y})";
    by (Blast_tac 1);
    qed "Collect_all_imp_eq";

    (*progress (2), step 4*)
    Goal "System : Always {s. ALL i<Nclients. \
    \                         ALL elt : set ((sub i o allocAsk) s). elt <= NbT}";
    by (auto_tac (claset(),  simpset() addsimps [Collect_all_imp_eq]));
    by (rtac (Always_Int_rule [Always_allocAsk_le_ask, System_Bounded_ask]
        RS Always_weaken) 1);
    by (auto_tac (claset() addDs [set_mono], simpset()));
    qed "System_Bounded_allocAsk";

    (*progress (2), step 5 is System_Increasing_allocGiv*)

    (*progress (2), step 6*)
    (* i < Nclients ==> System : Increasing (giv o sub i o client) *)
    bind_thm ("System_Increasing_giv",
              System_Follows_allocGiv RS Follows_Increasing1);

    Goal "i: I \
    \  ==> rename sysOfClient (plam x: I. rename client_map Client) \
    \       : Increasing (giv o sub i o client)  \
    \         guarantees \
    \         (INT h. {s. h <= (giv o sub i o client) s & \
    \                           h pfixGe (ask o sub i o client) s}  \
    \                 LeadsTo {s. tokens h <= (tokens o rel o sub i o client) s})";
    by rename_client_map_tac;
    by (asm_simp_tac (simpset() addsimps [o_simp Client_Progress]) 1);
    qed "rename_Client_Progress";

    (*progress (2), step 7*)
    Goal
     "System : (INT i : (lessThan Nclients). \
    \           INT h. {s. h <= (giv o sub i o client) s & \
    \                      h pfixGe (ask o sub i o client) s}  \
    \               LeadsTo {s. tokens h <= (tokens o rel o sub i o client) s})";
    by (rtac INT_I 1);
    (*Couldn't have just used Auto_tac since the "INT h" must be kept*)
    by (rtac ([rename_Client_Progress,
    	   Client_component_System] MRS component_guaranteesD) 1);
    by (auto_tac (claset(), simpset() addsimps [System_Increasing_giv]));
    qed "System_Client_Progress";

    (*Concludes
     System : {s. k <= (sub i o allocGiv) s}
              LeadsTo
              {s. (sub i o allocAsk) s <= (ask o sub i o client) s} Int
              {s. k <= (giv o sub i o client) s} *)
    val lemma =
        [System_Follows_ask RS Follows_Bounded,
         System_Follows_allocGiv RS Follows_LeadsTo] MRS Always_LeadsToD;

    (*A more complicated variant of the previous one*)
    val lemma2 = [lemma,
    	      System_Follows_ask RS Follows_Increasing1 RS IncreasingD]
                 MRS PSP_Stable;

    Goal "i < Nclients \
    \     ==> System : {s. h <= (sub i o allocGiv) s &      \
    \                      h pfixGe (sub i o allocAsk) s}   \
    \                  LeadsTo  \
    \                  {s. h <= (giv o sub i o client) s &  \
    \                      h pfixGe (ask o sub i o client) s}";
    by (rtac single_LeadsTo_I 1);
    by (res_inst_tac [("k6", "h"), ("x2", "(sub i o allocAsk) s")]
        (lemma2 RS LeadsTo_weaken) 1);
    by Auto_tac;
    by (blast_tac (claset() addIs [trans_Ge RS trans_genPrefix RS transD,
    			       prefix_imp_pfixGe]) 1);
    val lemma3 = result();

    (*progress (2), step 8: Client i's "release" action is visible system-wide*)
    Goal "i < Nclients  \
    \     ==> System : {s. h <= (sub i o allocGiv) s & \
    \                      h pfixGe (sub i o allocAsk) s}  \
    \                  LeadsTo {s. tokens h <= (tokens o sub i o allocRel) s}";
    by (rtac LeadsTo_Trans 1);
    by (dtac (System_Follows_rel RS impOfSubs (mono_tokens RS mono_Follows_o) RS
    	  Follows_LeadsTo) 2);
    by (asm_full_simp_tac (simpset() addsimps [o_assoc]) 2);
    by (rtac LeadsTo_Trans 1);
    by (cut_facts_tac [System_Client_Progress] 2);
    by (blast_tac (claset() addIs [LeadsTo_Basis]) 2);
    by (etac lemma3 1);
    qed "System_Alloc_Client_Progress";

    (*Lifting Alloc_Progress up to the level of systemState*)
    val rename_Alloc_Progress =
        Alloc_Progress RS rename_guarantees_sysOfAlloc_I
         |> simplify (simpset() addsimps [o_def]);

    (*progress (2), step 9*)
    Goal
     "System : (INT i : (lessThan Nclients). \
    \           INT h. {s. h <= (sub i o allocAsk) s}  \
    \                  LeadsTo {s. h pfixLe (sub i o allocGiv) s})";
    (*Can't use simpset(): the "INT h" must be kept*)
    by (simp_tac (HOL_ss addsimps [o_apply, sub_def]) 1);
    by (rtac (rename_Alloc_Progress RS component_guaranteesD) 1);
    by (auto_tac (claset(),
    	      simpset() addsimps [o_simp System_Increasing_allocRel,
    				  o_simp System_Increasing_allocAsk,
    				  o_simp System_Bounded_allocAsk,
    				  o_simp System_Alloc_Client_Progress]));
    qed "System_Alloc_Progress";

    (*progress (2), step 10 (final result!) *)
    Goalw [system_progress_def] "System : system_progress";
    by (cut_facts_tac [System_Alloc_Progress] 1);
    by (blast_tac (claset() addIs [LeadsTo_Trans,
                    System_Follows_allocGiv RS Follows_LeadsTo_pfixLe,
                    System_Follows_ask RS Follows_LeadsTo]) 1);
    qed "System_Progress";

    (*Ultimate goal*)
    Goalw [system_spec_def] "System : system_spec";
    by (blast_tac (claset() addIs [System_safety, System_Progress]) 1);
    qed "System_correct";

    (** SOME lemmas no longer used **)

    Goal "non_dummy = (% (g,a,r). (| giv = g, ask = a, rel = r |)) o \
    \                             (funPair giv (funPair ask rel))";
    by (rtac ext 1);
    by (auto_tac (claset(), simpset() addsimps [o_def, non_dummy_def]));
    qed "non_dummy_eq_o_funPair";

    Goal "(preserves non_dummy) = \
    \     (preserves rel Int preserves ask Int preserves giv)";
    by (simp_tac (simpset() addsimps [non_dummy_eq_o_funPair]) 1);
    by Auto_tac;
    by (dres_inst_tac [("w1", "rel")] (impOfSubs subset_preserves_o) 1);
    by (dres_inst_tac [("w1", "ask")] (impOfSubs subset_preserves_o) 2);
    by (dres_inst_tac [("w1", "giv")] (impOfSubs subset_preserves_o) 3);
    by (auto_tac (claset(), simpset() addsimps [o_def]));
    qed "preserves_non_dummy_eq";

    (*Could go to Extend.ML*)
    Goal "bij f ==> fst (inv (%(x, u). inv f x) z) = f z";
    by (rtac fst_inv_equalityI 1);
    by (res_inst_tac [("f","%z. (f z, ?h z)")] surjI 1);
    by (asm_full_simp_tac (simpset() addsimps [bij_is_inj, inv_f_f]) 1);
    by (asm_full_simp_tac (simpset() addsimps [bij_is_surj, surj_f_inv_f]) 1);
    qed "bij_fst_inv_inv_eq";