Theory Rank_Separation (Isabelle2005: October 2005)

# Theory Rank_Separation

Up to index of Isabelle/ZF/Constructible

theory Rank_Separation
imports Rank Rec_Separation
begin

    (*  Title:      ZF/Constructible/Rank_Separation.thy
        ID:   $Id: Rank_Separation.thy,v 1.4 2005/06/17 14:15:10 haftmann Exp $
        Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
    *)

    header {*Separation for Facts About Order Types, Rank Functions and
          Well-Founded Relations*}

    theory Rank_Separation imports Rank Rec_Separation begin

    text{*This theory proves all instances needed for locales
     @{text "M_ordertype"} and  @{text "M_wfrank"}.  But the material is not
     needed for proving the relative consistency of AC.*}

    subsection{*The Locale @{text "M_ordertype"}*}

    subsubsection{*Separation for Order-Isomorphisms*}

    lemma well_ord_iso_Reflects:
      "REFLECTS[λx. x∈A -->
                    (∃y[L]. ∃p[L]. fun_apply(L,f,x,y) & pair(L,y,x,p) & p ∈ r),
            λi x. x∈A --> (∃y ∈ Lset(i). ∃p ∈ Lset(i).
                    fun_apply(##Lset(i),f,x,y) & pair(##Lset(i),y,x,p) & p ∈ r)]"
    by (intro FOL_reflections function_reflections)

    lemma well_ord_iso_separation:
         "[| L(A); L(f); L(r) |]
          ==> separation (L, λx. x∈A --> (∃y[L]. (∃p[L].
                         fun_apply(L,f,x,y) & pair(L,y,x,p) & p ∈ r)))"
    apply (rule gen_separation_multi [OF well_ord_iso_Reflects, of "{A,f,r}"],
           auto)
    apply (rule_tac env="[A,f,r]" in DPow_LsetI)
    apply (rule sep_rules | simp)+
    done

    subsubsection{*Separation for @{term "obase"}*}

    lemma obase_reflects:
      "REFLECTS[λa. ∃x[L]. ∃g[L]. ∃mx[L]. ∃par[L].
                 ordinal(L,x) & membership(L,x,mx) & pred_set(L,A,a,r,par) &
                 order_isomorphism(L,par,r,x,mx,g),
            λi a. ∃x ∈ Lset(i). ∃g ∈ Lset(i). ∃mx ∈ Lset(i). ∃par ∈ Lset(i).
                 ordinal(##Lset(i),x) & membership(##Lset(i),x,mx) & pred_set(##Lset(i),A,a,r,par) &
                 order_isomorphism(##Lset(i),par,r,x,mx,g)]"
    by (intro FOL_reflections function_reflections fun_plus_reflections)

    lemma obase_separation:
         --{*part of the order type formalization*}
         "[| L(A); L(r) |]
          ==> separation(L, λa. ∃x[L]. ∃g[L]. ∃mx[L]. ∃par[L].
                 ordinal(L,x) & membership(L,x,mx) & pred_set(L,A,a,r,par) &
                 order_isomorphism(L,par,r,x,mx,g))"
    apply (rule gen_separation_multi [OF obase_reflects, of "{A,r}"], auto)
    apply (rule_tac env="[A,r]" in DPow_LsetI)
    apply (rule ordinal_iff_sats sep_rules | simp)+
    done

    subsubsection{*Separation for a Theorem about @{term "obase"}*}

    lemma obase_equals_reflects:
      "REFLECTS[λx. x∈A --> ~(∃y[L]. ∃g[L].
                    ordinal(L,y) & (∃my[L]. ∃pxr[L].
                    membership(L,y,my) & pred_set(L,A,x,r,pxr) &
                    order_isomorphism(L,pxr,r,y,my,g))),
            λi x. x∈A --> ~(∃y ∈ Lset(i). ∃g ∈ Lset(i).
                    ordinal(##Lset(i),y) & (∃my ∈ Lset(i). ∃pxr ∈ Lset(i).
                    membership(##Lset(i),y,my) & pred_set(##Lset(i),A,x,r,pxr) &
                    order_isomorphism(##Lset(i),pxr,r,y,my,g)))]"
    by (intro FOL_reflections function_reflections fun_plus_reflections)

    lemma obase_equals_separation:
         "[| L(A); L(r) |]
          ==> separation (L, λx. x∈A --> ~(∃y[L]. ∃g[L].
                                  ordinal(L,y) & (∃my[L]. ∃pxr[L].
                                  membership(L,y,my) & pred_set(L,A,x,r,pxr) &
                                  order_isomorphism(L,pxr,r,y,my,g))))"
    apply (rule gen_separation_multi [OF obase_equals_reflects, of "{A,r}"], auto)
    apply (rule_tac env="[A,r]" in DPow_LsetI)
    apply (rule sep_rules | simp)+
    done

    subsubsection{*Replacement for @{term "omap"}*}

    lemma omap_reflects:
     "REFLECTS[λz. ∃a[L]. a∈B & (∃x[L]. ∃g[L]. ∃mx[L]. ∃par[L].
         ordinal(L,x) & pair(L,a,x,z) & membership(L,x,mx) &
         pred_set(L,A,a,r,par) & order_isomorphism(L,par,r,x,mx,g)),
     λi z. ∃a ∈ Lset(i). a∈B & (∃x ∈ Lset(i). ∃g ∈ Lset(i). ∃mx ∈ Lset(i).
            ∃par ∈ Lset(i).
             ordinal(##Lset(i),x) & pair(##Lset(i),a,x,z) &
             membership(##Lset(i),x,mx) & pred_set(##Lset(i),A,a,r,par) &
             order_isomorphism(##Lset(i),par,r,x,mx,g))]"
    by (intro FOL_reflections function_reflections fun_plus_reflections)

    lemma omap_replacement:
         "[| L(A); L(r) |]
          ==> strong_replacement(L,
                 λa z. ∃x[L]. ∃g[L]. ∃mx[L]. ∃par[L].
                 ordinal(L,x) & pair(L,a,x,z) & membership(L,x,mx) &
                 pred_set(L,A,a,r,par) & order_isomorphism(L,par,r,x,mx,g))"
    apply (rule strong_replacementI)
    apply (rule_tac u="{A,r,B}" in gen_separation_multi [OF omap_reflects], auto)
    apply (rule_tac env="[A,B,r]" in DPow_LsetI)
    apply (rule sep_rules | simp)+
    done

    subsection{*Instantiating the locale @{text M_ordertype}*}
    text{*Separation (and Strong Replacement) for basic set-theoretic constructions
    such as intersection, Cartesian Product and image.*}

    lemma M_ordertype_axioms_L: "M_ordertype_axioms(L)"
      apply (rule M_ordertype_axioms.intro)
           apply (assumption | rule well_ord_iso_separation
             obase_separation obase_equals_separation
             omap_replacement)+
      done

    theorem M_ordertype_L: "PROP M_ordertype(L)"
    apply (rule M_ordertype.intro)
         apply (rule M_basic.axioms [OF M_basic_L])+
    apply (rule M_ordertype_axioms_L)
    done

    subsection{*The Locale @{text "M_wfrank"}*}

    subsubsection{*Separation for @{term "wfrank"}*}

    lemma wfrank_Reflects:
     "REFLECTS[λx. ∀rplus[L]. tran_closure(L,r,rplus) -->
                  ~ (∃f[L]. M_is_recfun(L, %x f y. is_range(L,f,y), rplus, x, f)),
          λi x. ∀rplus ∈ Lset(i). tran_closure(##Lset(i),r,rplus) -->
             ~ (∃f ∈ Lset(i).
                M_is_recfun(##Lset(i), %x f y. is_range(##Lset(i),f,y),
                            rplus, x, f))]"
    by (intro FOL_reflections function_reflections is_recfun_reflection tran_closure_reflection)

    lemma wfrank_separation:
         "L(r) ==>
          separation (L, λx. ∀rplus[L]. tran_closure(L,r,rplus) -->
             ~ (∃f[L]. M_is_recfun(L, %x f y. is_range(L,f,y), rplus, x, f)))"
    apply (rule gen_separation [OF wfrank_Reflects], simp)
    apply (rule_tac env="[r]" in DPow_LsetI)
    apply (rule sep_rules tran_closure_iff_sats is_recfun_iff_sats | simp)+
    done

    subsubsection{*Replacement for @{term "wfrank"}*}

    lemma wfrank_replacement_Reflects:
     "REFLECTS[λz. ∃x[L]. x ∈ A &
            (∀rplus[L]. tran_closure(L,r,rplus) -->
             (∃y[L]. ∃f[L]. pair(L,x,y,z)  &
                            M_is_recfun(L, %x f y. is_range(L,f,y), rplus, x, f) &
                            is_range(L,f,y))),
     λi z. ∃x ∈ Lset(i). x ∈ A &
          (∀rplus ∈ Lset(i). tran_closure(##Lset(i),r,rplus) -->
           (∃y ∈ Lset(i). ∃f ∈ Lset(i). pair(##Lset(i),x,y,z)  &
             M_is_recfun(##Lset(i), %x f y. is_range(##Lset(i),f,y), rplus, x, f) &
             is_range(##Lset(i),f,y)))]"
    by (intro FOL_reflections function_reflections fun_plus_reflections
                 is_recfun_reflection tran_closure_reflection)

    lemma wfrank_strong_replacement:
         "L(r) ==>
          strong_replacement(L, λx z.
             ∀rplus[L]. tran_closure(L,r,rplus) -->
             (∃y[L]. ∃f[L]. pair(L,x,y,z)  &
                            M_is_recfun(L, %x f y. is_range(L,f,y), rplus, x, f) &
                            is_range(L,f,y)))"
    apply (rule strong_replacementI)
    apply (rule_tac u="{r,B}"
             in gen_separation_multi [OF wfrank_replacement_Reflects],
           auto)
    apply (rule_tac env="[r,B]" in DPow_LsetI)
    apply (rule sep_rules tran_closure_iff_sats is_recfun_iff_sats | simp)+
    done

    subsubsection{*Separation for Proving @{text Ord_wfrank_range}*}

    lemma Ord_wfrank_Reflects:
     "REFLECTS[λx. ∀rplus[L]. tran_closure(L,r,rplus) -->
              ~ (∀f[L]. ∀rangef[L].
                 is_range(L,f,rangef) -->
                 M_is_recfun(L, λx f y. is_range(L,f,y), rplus, x, f) -->
                 ordinal(L,rangef)),
          λi x. ∀rplus ∈ Lset(i). tran_closure(##Lset(i),r,rplus) -->
              ~ (∀f ∈ Lset(i). ∀rangef ∈ Lset(i).
                 is_range(##Lset(i),f,rangef) -->
                 M_is_recfun(##Lset(i), λx f y. is_range(##Lset(i),f,y),
                             rplus, x, f) -->
                 ordinal(##Lset(i),rangef))]"
    by (intro FOL_reflections function_reflections is_recfun_reflection
              tran_closure_reflection ordinal_reflection)

    lemma  Ord_wfrank_separation:
         "L(r) ==>
          separation (L, λx.
             ∀rplus[L]. tran_closure(L,r,rplus) -->
              ~ (∀f[L]. ∀rangef[L].
                 is_range(L,f,rangef) -->
                 M_is_recfun(L, λx f y. is_range(L,f,y), rplus, x, f) -->
                 ordinal(L,rangef)))"
    apply (rule gen_separation [OF Ord_wfrank_Reflects], simp)
    apply (rule_tac env="[r]" in DPow_LsetI)
    apply (rule sep_rules tran_closure_iff_sats is_recfun_iff_sats | simp)+
    done

    subsubsection{*Instantiating the locale @{text M_wfrank}*}

    lemma M_wfrank_axioms_L: "M_wfrank_axioms(L)"
      apply (rule M_wfrank_axioms.intro)
       apply (assumption | rule
         wfrank_separation wfrank_strong_replacement Ord_wfrank_separation)+
      done

    theorem M_wfrank_L: "PROP M_wfrank(L)"
      apply (rule M_wfrank.intro)
         apply (rule M_trancl.axioms [OF M_trancl_L])+
      apply (rule M_wfrank_axioms_L)
      done

    lemmas exists_wfrank = M_wfrank.exists_wfrank [OF M_wfrank_L]
      and M_wellfoundedrank = M_wfrank.M_wellfoundedrank [OF M_wfrank_L]
      and Ord_wfrank_range = M_wfrank.Ord_wfrank_range [OF M_wfrank_L]
      and Ord_range_wellfoundedrank = M_wfrank.Ord_range_wellfoundedrank [OF M_wfrank_L]
      and function_wellfoundedrank = M_wfrank.function_wellfoundedrank [OF M_wfrank_L]
      and domain_wellfoundedrank = M_wfrank.domain_wellfoundedrank [OF M_wfrank_L]
      and wellfoundedrank_type = M_wfrank.wellfoundedrank_type [OF M_wfrank_L]
      and Ord_wellfoundedrank = M_wfrank.Ord_wellfoundedrank [OF M_wfrank_L]
      and wellfoundedrank_eq = M_wfrank.wellfoundedrank_eq [OF M_wfrank_L]
      and wellfoundedrank_lt = M_wfrank.wellfoundedrank_lt [OF M_wfrank_L]
      and wellfounded_imp_subset_rvimage = M_wfrank.wellfounded_imp_subset_rvimage [OF M_wfrank_L]
      and wellfounded_imp_wf = M_wfrank.wellfounded_imp_wf [OF M_wfrank_L]
      and wellfounded_on_imp_wf_on = M_wfrank.wellfounded_on_imp_wf_on [OF M_wfrank_L]
      and wf_abs = M_wfrank.wf_abs [OF M_wfrank_L]
      and wf_on_abs = M_wfrank.wf_on_abs [OF M_wfrank_L]

    end

### The Locale @{text "M_ordertype"}

#### Separation for Order-Isomorphisms

lemma well_ord_iso_Reflects:

      REFLECTS
         [%x. x ∈ A -->
              (∃y[L]. ∃p[L]. fun_apply(L, f, x, y) ∧ pair(L, y, x, p) ∧ p ∈ r),
         %i x. x ∈ A -->
               (∃y∈Lset(i).
                   ∃p∈Lset(i).
                      fun_apply(##Lset(i), f, x, y) ∧
                      pair(##Lset(i), y, x, p) ∧ p ∈ r)]

lemma well_ord_iso_separation:

      [| L(A); L(f); L(r) |]
      ==> separation
           (L, %x. x ∈ A -->
                   (∃y[L]. ∃p[L]. fun_apply(L, f, x, y) ∧ pair(L, y, x, p) ∧ p ∈ r))

#### Separation for @{term "obase"}

lemma obase_reflects:

      REFLECTS
         [%a. ∃x[L]. ∃g[L]. ∃mx[L].
                               ∃par[L].
                                  ordinal(L, x) ∧
                                  membership(L, x, mx) ∧
                                  pred_set(L, A, a, r, par) ∧
                                  order_isomorphism(L, par, r, x, mx, g),
         %i a. ∃x∈Lset(i).
                  ∃g∈Lset(i).
                     ∃mx∈Lset(i).
                        ∃par∈Lset(i).
                           ordinal(##Lset(i), x) ∧
                           membership(##Lset(i), x, mx) ∧
                           pred_set(##Lset(i), A, a, r, par) ∧
                           order_isomorphism(##Lset(i), par, r, x, mx, g)]

lemma obase_separation:

      [| L(A); L(r) |]
      ==> separation
           (L, %a. ∃x[L]. ∃g[L]. ∃mx[L].
                                    ∃par[L].
                                       ordinal(L, x) ∧
                                       membership(L, x, mx) ∧
                                       pred_set(L, A, a, r, par) ∧
                                       order_isomorphism(L, par, r, x, mx, g))

#### Separation for a Theorem about @{term "obase"}

lemma obase_equals_reflects:

      REFLECTS
         [%x. x ∈ A -->
              ¬ (∃y[L]. ∃g[L]. ordinal(L, y) ∧
                               (∃my[L].
                                   ∃pxr[L].
                                      membership(L, y, my) ∧
                                      pred_set(L, A, x, r, pxr) ∧
                                      order_isomorphism(L, pxr, r, y, my, g))),
         %i x. x ∈ A -->
               ¬ (∃y∈Lset(i).
                     ∃g∈Lset(i).
                        ordinal(##Lset(i), y) ∧
                        (∃my∈Lset(i).
                            ∃pxr∈Lset(i).
                               membership(##Lset(i), y, my) ∧
                               pred_set(##Lset(i), A, x, r, pxr) ∧
                               order_isomorphism(##Lset(i), pxr, r, y, my, g)))]

lemma obase_equals_separation:

      [| L(A); L(r) |]
      ==> separation
           (L, %x. x ∈ A -->
                   ¬ (∃y[L]. ∃g[L]. ordinal(L, y) ∧
                                    (∃my[L].
                                        ∃pxr[L].
                                           membership(L, y, my) ∧
                                           pred_set(L, A, x, r, pxr) ∧
                                           order_isomorphism(L, pxr, r, y, my, g))))

#### Replacement for @{term "omap"}

lemma omap_reflects:

      REFLECTS
         [%z. ∃a[L]. a ∈ B ∧
                     (∃x[L]. ∃g[L]. ∃mx[L].
                                       ∃par[L].
                                          ordinal(L, x) ∧
                                          pair(L, a, x, z) ∧
                                          membership(L, x, mx) ∧
                                          pred_set(L, A, a, r, par) ∧
                                          order_isomorphism(L, par, r, x, mx, g)),
         %i z. ∃a∈Lset(i).
                  a ∈ B ∧
                  (∃x∈Lset(i).
                      ∃g∈Lset(i).
                         ∃mx∈Lset(i).
                            ∃par∈Lset(i).
                               ordinal(##Lset(i), x) ∧
                               pair(##Lset(i), a, x, z) ∧
                               membership(##Lset(i), x, mx) ∧
                               pred_set(##Lset(i), A, a, r, par) ∧
                               order_isomorphism(##Lset(i), par, r, x, mx, g))]

lemma omap_replacement:

      [| L(A); L(r) |]
      ==> strong_replacement
           (L, %a z. ∃x[L]. ∃g[L]. ∃mx[L].
                                      ∃par[L].
                                         ordinal(L, x) ∧
                                         pair(L, a, x, z) ∧
                                         membership(L, x, mx) ∧
                                         pred_set(L, A, a, r, par) ∧
                                         order_isomorphism(L, par, r, x, mx, g))

### Instantiating the locale @{text M_ordertype}

lemma M_ordertype_axioms_L:

      M_ordertype_axioms(L)

theorem M_ordertype_L:

      PROP M_ordertype(L)

### The Locale @{text "M_wfrank"}

#### Separation for @{term "wfrank"}

lemma wfrank_Reflects:

      REFLECTS
         [%x. ∀rplus[L].
                 tran_closure(L, r, rplus) -->
                 ¬ (∃f[L]. M_is_recfun(L, %x f y. is_range(L, f, y), rplus, x, f)),
         %i x. ∀rplus∈Lset(i).
                  tran_closure(##Lset(i), r, rplus) -->
                  ¬ (∃f∈Lset(i).
                        M_is_recfun
                         (##Lset(i), %x f y. is_range(##Lset(i), f, y), rplus, x, f))]

lemma wfrank_separation:

      L(r)
      ==> separation
           (L, %x. ∀rplus[L].
                      tran_closure(L, r, rplus) -->
                      ¬ (∃f[L]. M_is_recfun
                                 (L, %x f y. is_range(L, f, y), rplus, x, f)))

#### Replacement for @{term "wfrank"}

lemma wfrank_replacement_Reflects:

      REFLECTS
         [%z. ∃x[L]. x ∈ A ∧
                     (∀rplus[L].
                         tran_closure(L, r, rplus) -->
                         (∃y[L]. ∃f[L]. pair(L, x, y, z) ∧
                                        M_is_recfun
                                         (L, %x f y. is_range(L, f, y), rplus, x, f) ∧
                                        is_range(L, f, y))),
         %i z. ∃x∈Lset(i).
                  x ∈ A ∧
                  (∀rplus∈Lset(i).
                      tran_closure(##Lset(i), r, rplus) -->
                      (∃y∈Lset(i).
                          ∃f∈Lset(i).
                             pair(##Lset(i), x, y, z) ∧
                             M_is_recfun
                              (##Lset(i), %x f y. is_range(##Lset(i), f, y), rplus, x,
                               f) ∧
                             is_range(##Lset(i), f, y)))]

lemma wfrank_strong_replacement:

      L(r)
      ==> strong_replacement
           (L, %x z. ∀rplus[L].
                        tran_closure(L, r, rplus) -->
                        (∃y[L]. ∃f[L]. pair(L, x, y, z) ∧
                                       M_is_recfun
                                        (L, %x f y. is_range(L, f, y), rplus, x, f) ∧
                                       is_range(L, f, y)))

#### Separation for Proving @{text Ord_wfrank_range}

lemma Ord_wfrank_Reflects:

      REFLECTS
         [%x. ∀rplus[L].
                 tran_closure(L, r, rplus) -->
                 ¬ (∀f[L]. ∀rangef[L].
                              is_range(L, f, rangef) -->
                              M_is_recfun
                               (L, %x f y. is_range(L, f, y), rplus, x, f) -->
                              ordinal(L, rangef)),
         %i x. ∀rplus∈Lset(i).
                  tran_closure(##Lset(i), r, rplus) -->
                  ¬ (∀f∈Lset(i).
                        ∀rangef∈Lset(i).
                           is_range(##Lset(i), f, rangef) -->
                           M_is_recfun
                            (##Lset(i), %x f y. is_range(##Lset(i), f, y), rplus, x,
                             f) -->
                           ordinal(##Lset(i), rangef))]

lemma Ord_wfrank_separation:

      L(r)
      ==> separation
           (L, %x. ∀rplus[L].
                      tran_closure(L, r, rplus) -->
                      ¬ (∀f[L]. ∀rangef[L].
                                   is_range(L, f, rangef) -->
                                   M_is_recfun
                                    (L, %x f y. is_range(L, f, y), rplus, x, f) -->
                                   ordinal(L, rangef)))

#### Instantiating the locale @{text M_wfrank}

lemma M_wfrank_axioms_L:

      M_wfrank_axioms(L)

theorem M_wfrank_L:

      PROP M_wfrank(L)

lemmas exists_wfrank:

      [| wellfounded(L, r); L(a); L(r) |]
      ==> ∃f[L]. is_recfun(r^+, a, %x f. range(f), f)

and M_wellfoundedrank:

      [| wellfounded(L, r); L(r); L(A) |] ==> L(wellfoundedrank(L, r, A))

and Ord_wfrank_range:

      [| wellfounded(L, r); a ∈ A; L(r); L(A) |]
      ==> ∀f[L]. is_recfun(r^+, a, %x f. range(f), f) --> Ord(range(f))

and Ord_range_wellfoundedrank:

      [| wellfounded(L, r); r ⊆ A × A; L(r); L(A) |]
      ==> Ord(range(wellfoundedrank(L, r, A)))

and function_wellfoundedrank:

      [| wellfounded(L, r); L(r); L(A) |] ==> function(wellfoundedrank(L, r, A))

and domain_wellfoundedrank:

      [| wellfounded(L, r); L(r); L(A) |] ==> domain(wellfoundedrank(L, r, A)) = A

and wellfoundedrank_type:

      [| wellfounded(L, r); L(r); L(A) |]
      ==> wellfoundedrank(L, r, A) ∈ A -> range(wellfoundedrank(L, r, A))

and Ord_wellfoundedrank:

      [| wellfounded(L, r); a ∈ A; r ⊆ A × A; L(r); L(A) |]
      ==> Ord(wellfoundedrank(L, r, A) ` a)

and wellfoundedrank_eq:

      [| is_recfun(r^+, a, %x. range, f); wellfounded(L, r); a ∈ A; L(f); L(r);
         L(A) |]
      ==> wellfoundedrank(L, r, A) ` a = range(f)

and wellfoundedrank_lt:

      [| ⟨a, b⟩ ∈ r; wellfounded(L, r); r ⊆ A × A; L(r); L(A) |]
      ==> wellfoundedrank(L, r, A) ` a < wellfoundedrank(L, r, A) ` b

and wellfounded_imp_subset_rvimage:

      [| wellfounded(L, r); r ⊆ A × A; L(r); L(A) |]
      ==> ∃i f. Ord(i) ∧ r ⊆ rvimage(A, f, Memrel(i))

and wellfounded_imp_wf:

      [| wellfounded(L, r); relation(r); L(r) |] ==> wf(r)

and wellfounded_on_imp_wf_on:

      [| wellfounded_on(L, A, r); relation(r); L(r); L(A) |] ==> wf[A](r)

and wf_abs:

      [| relation(r); L(r) |] ==> wellfounded(L, r) <-> wf(r)

and wf_on_abs:

      [| relation(r); L(r); L(A) |] ==> wellfounded_on(L, A, r) <-> wf[A](r)

lemmas exists_wfrank:

      [| wellfounded(L, r); L(a); L(r) |]
      ==> ∃f[L]. is_recfun(r^+, a, %x f. range(f), f)

and M_wellfoundedrank:

      [| wellfounded(L, r); L(r); L(A) |] ==> L(wellfoundedrank(L, r, A))

and Ord_wfrank_range:

      [| wellfounded(L, r); a ∈ A; L(r); L(A) |]
      ==> ∀f[L]. is_recfun(r^+, a, %x f. range(f), f) --> Ord(range(f))

and Ord_range_wellfoundedrank:

      [| wellfounded(L, r); r ⊆ A × A; L(r); L(A) |]
      ==> Ord(range(wellfoundedrank(L, r, A)))

and function_wellfoundedrank:

      [| wellfounded(L, r); L(r); L(A) |] ==> function(wellfoundedrank(L, r, A))

and domain_wellfoundedrank:

      [| wellfounded(L, r); L(r); L(A) |] ==> domain(wellfoundedrank(L, r, A)) = A

and wellfoundedrank_type:

      [| wellfounded(L, r); L(r); L(A) |]
      ==> wellfoundedrank(L, r, A) ∈ A -> range(wellfoundedrank(L, r, A))

and Ord_wellfoundedrank:

      [| wellfounded(L, r); a ∈ A; r ⊆ A × A; L(r); L(A) |]
      ==> Ord(wellfoundedrank(L, r, A) ` a)

and wellfoundedrank_eq:

      [| is_recfun(r^+, a, %x. range, f); wellfounded(L, r); a ∈ A; L(f); L(r);
         L(A) |]
      ==> wellfoundedrank(L, r, A) ` a = range(f)

and wellfoundedrank_lt:

      [| ⟨a, b⟩ ∈ r; wellfounded(L, r); r ⊆ A × A; L(r); L(A) |]
      ==> wellfoundedrank(L, r, A) ` a < wellfoundedrank(L, r, A) ` b

and wellfounded_imp_subset_rvimage:

      [| wellfounded(L, r); r ⊆ A × A; L(r); L(A) |]
      ==> ∃i f. Ord(i) ∧ r ⊆ rvimage(A, f, Memrel(i))

and wellfounded_imp_wf:

      [| wellfounded(L, r); relation(r); L(r) |] ==> wf(r)

and wellfounded_on_imp_wf_on:

      [| wellfounded_on(L, A, r); relation(r); L(r); L(A) |] ==> wf[A](r)

and wf_abs:

      [| relation(r); L(r) |] ==> wellfounded(L, r) <-> wf(r)

and wf_on_abs:

      [| relation(r); L(r); L(A) |] ==> wellfounded_on(L, A, r) <-> wf[A](r)