Nuprl Lemma : bs_tree_ind_wf
∀[E,A:Type]. ∀[R:A ⟶ bs_tree(E) ⟶ ℙ]. ∀[v:bs_tree(E)]. ∀[null:{x:A| R[x;bst_null()]} ].
∀[leaf:value:E ⟶ {x:A| R[x;bst_leaf(value)]} ]. ∀[node:left:bs_tree(E)
                                                       ⟶ value:E
                                                       ⟶ right:bs_tree(E)
                                                       ⟶ {x:A| R[x;left]} 
                                                       ⟶ {x:A| R[x;right]} 
                                                       ⟶ {x:A| R[x;bst_node(left;value;right)]} ].
  (case(v)
   null=>null
   leaf(value)=>leaf[value]
   node(left,value,right)=>rec1,rec2.node[left;value;right;rec1;rec2] ∈ {x:A| R[x;v]} )
Proof
Definitions occuring in Statement : 
bs_tree_ind: bs_tree_ind, 
bst_node: bst_node(left;value;right)
, 
bst_leaf: bst_leaf(value)
, 
bst_null: bst_null()
, 
bs_tree: bs_tree(E)
, 
uall: ∀[x:A]. B[x]
, 
prop: ℙ
, 
so_apply: x[s1;s2;s3;s4;s5]
, 
so_apply: x[s1;s2]
, 
so_apply: x[s]
, 
member: t ∈ T
, 
set: {x:A| B[x]} 
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
bs_tree_ind: bs_tree_ind, 
so_apply: x[s1;s2;s3;s4;s5]
, 
so_apply: x[s]
, 
so_apply: x[s1;s2]
, 
bs_tree-definition, 
bs_tree-induction, 
uniform-comp-nat-induction, 
bs_tree-ext, 
eq_atom: x =a y
, 
btrue: tt
, 
it: ⋅
, 
bfalse: ff
, 
bool_cases_sqequal, 
eqff_to_assert, 
any: any x
, 
all: ∀x:A. B[x]
, 
implies: P 
⇒ Q
, 
has-value: (a)↓
, 
so_lambda: so_lambda4, 
so_apply: x[s1;s2;s3;s4]
, 
so_lambda: λ2x.t[x]
, 
uimplies: b supposing a
, 
subtype_rel: A ⊆r B
, 
prop: ℙ
, 
guard: {T}
Lemmas referenced : 
bs_tree-definition, 
has-value_wf_base, 
is-exception_wf, 
lifting-strict-atom_eq, 
strict4-decide, 
bs_tree_wf, 
bst_null_wf, 
bst_leaf_wf, 
bst_node_wf, 
subtype_rel_function, 
subtype_rel_self, 
istype-universe, 
bs_tree-induction, 
uniform-comp-nat-induction, 
bs_tree-ext, 
bool_cases_sqequal, 
eqff_to_assert
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation_alt, 
cut, 
sqequalRule, 
Error :memTop, 
inhabitedIsType, 
hypothesis, 
lambdaFormation_alt, 
thin, 
sqequalSqle, 
divergentSqle, 
callbyvalueDecide, 
sqequalHypSubstitution, 
hypothesisEquality, 
unionElimination, 
sqleReflexivity, 
equalityIstype, 
equalityTransitivity, 
equalitySymmetry, 
dependent_functionElimination, 
independent_functionElimination, 
introduction, 
decideExceptionCases, 
axiomSqleEquality, 
exceptionSqequal, 
baseApply, 
closedConclusion, 
baseClosed, 
extract_by_obid, 
isectElimination, 
independent_isectElimination, 
lambdaEquality_alt, 
isectIsType, 
because_Cache, 
functionIsType, 
universeIsType, 
universeEquality, 
setIsType, 
applyEquality, 
functionEquality, 
setEquality, 
instantiate, 
functionExtensionality
Latex:
\mforall{}[E,A:Type].  \mforall{}[R:A  {}\mrightarrow{}  bs\_tree(E)  {}\mrightarrow{}  \mBbbP{}].  \mforall{}[v:bs\_tree(E)].  \mforall{}[null:\{x:A|  R[x;bst\_null()]\}  ].
\mforall{}[leaf:value:E  {}\mrightarrow{}  \{x:A|  R[x;bst\_leaf(value)]\}  ].  \mforall{}[node:left:bs\_tree(E)
                                                                                                              {}\mrightarrow{}  value:E
                                                                                                              {}\mrightarrow{}  right:bs\_tree(E)
                                                                                                              {}\mrightarrow{}  \{x:A|  R[x;left]\} 
                                                                                                              {}\mrightarrow{}  \{x:A|  R[x;right]\} 
                                                                                                              {}\mrightarrow{}  \{x:A|  R[x;bst\_node(left;value;right)]\}  ].
    (case(v)
      null=>null
      leaf(value)=>leaf[value]
      node(left,value,right)=>rec1,rec2.node[left;value;right;rec1;rec2]  \mmember{}  \{x:A|  R[x;v]\}  )
Date html generated:
2020_05_20-AM-07_48_04
Last ObjectModification:
2020_02_03-PM-02_57_24
Theory : tree_1
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