Nuprl Lemma : tree-induction
∀[E:Type]. ∀[P:tree(E) ⟶ ℙ].
  ((∀value:E. P[tree_leaf(value)])
  ⇒ (∀left,right:tree(E).  (P[left] ⇒ P[right] ⇒ P[tree_node(left;right)]))
  ⇒ {∀v:tree(E). P[v]})
Proof
Definitions occuring in Statement : 
tree_node: tree_node(left;right), 
tree_leaf: tree_leaf(value), 
tree: tree(E), 
uall: ∀[x:A]. B[x], 
prop: ℙ, 
guard: {T}, 
so_apply: x[s], 
all: ∀x:A. B[x], 
implies: P ⇒ Q, 
function: x:A ⟶ B[x], 
universe: Type
Definitions unfolded in proof : 
uall: ∀[x:A]. B[x], 
implies: P ⇒ Q, 
guard: {T}, 
so_lambda: λ2x.t[x], 
member: t ∈ T, 
uimplies: b supposing a, 
subtype_rel: A ⊆r B, 
nat: ℕ, 
prop: ℙ, 
so_apply: x[s], 
all: ∀x:A. B[x], 
le: A ≤ B, 
and: P ∧ Q, 
not: ¬A, 
false: False, 
ext-eq: A ≡ B, 
bool: 𝔹, 
unit: Unit, 
it: ⋅, 
btrue: tt, 
uiff: uiff(P;Q), 
sq_type: SQType(T), 
eq_atom: x =a y, 
ifthenelse: if b then t else f fi , 
tree_leaf: tree_leaf(value), 
tree_size: tree_size(p), 
bfalse: ff, 
exists: ∃x:A. B[x], 
or: P ∨ Q, 
bnot: ¬bb, 
assert: ↑b, 
tree_node: tree_node(left;right), 
cand: A c∧ B, 
ge: i ≥ j , 
decidable: Dec(P), 
satisfiable_int_formula: satisfiable_int_formula(fmla), 
top: Top, 
int_seg: {i..j-}, 
lelt: i ≤ j < k, 
less_than: a < b, 
squash: ↓T
Lemmas referenced : 
uniform-comp-nat-induction, 
all_wf, 
tree_wf, 
isect_wf, 
le_wf, 
tree_size_wf, 
nat_wf, 
less_than'_wf, 
tree-ext, 
eq_atom_wf, 
bool_wf, 
eqtt_to_assert, 
assert_of_eq_atom, 
subtype_base_sq, 
atom_subtype_base, 
eqff_to_assert, 
equal_wf, 
bool_cases_sqequal, 
bool_subtype_base, 
assert-bnot, 
neg_assert_of_eq_atom, 
nat_properties, 
decidable__lt, 
satisfiable-full-omega-tt, 
intformand_wf, 
intformnot_wf, 
intformless_wf, 
itermConstant_wf, 
itermVar_wf, 
intformle_wf, 
itermAdd_wf, 
int_formula_prop_and_lemma, 
int_formula_prop_not_lemma, 
int_formula_prop_less_lemma, 
int_term_value_constant_lemma, 
int_term_value_var_lemma, 
int_formula_prop_le_lemma, 
int_term_value_add_lemma, 
int_formula_prop_wf, 
subtract_wf, 
decidable__le, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
lelt_wf, 
uall_wf, 
int_seg_wf, 
tree_node_wf, 
tree_leaf_wf
Rules used in proof : 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
isect_memberFormation, 
lambdaFormation, 
cut, 
introduction, 
extract_by_obid, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
sqequalRule, 
lambdaEquality, 
cumulativity, 
hypothesisEquality, 
hypothesis, 
applyEquality, 
because_Cache, 
setElimination, 
rename, 
functionExtensionality, 
independent_functionElimination, 
productElimination, 
independent_pairEquality, 
dependent_functionElimination, 
voidElimination, 
axiomEquality, 
equalityTransitivity, 
equalitySymmetry, 
promote_hyp, 
hypothesis_subsumption, 
tokenEquality, 
unionElimination, 
equalityElimination, 
independent_isectElimination, 
instantiate, 
atomEquality, 
dependent_pairFormation, 
independent_pairFormation, 
applyLambdaEquality, 
natural_numberEquality, 
int_eqEquality, 
intEquality, 
isect_memberEquality, 
voidEquality, 
computeAll, 
dependent_set_memberEquality, 
imageElimination, 
functionEquality, 
universeEquality
Latex:
\mforall{}[E:Type].  \mforall{}[P:tree(E)  {}\mrightarrow{}  \mBbbP{}].
    ((\mforall{}value:E.  P[tree\_leaf(value)])
    {}\mRightarrow{}  (\mforall{}left,right:tree(E).    (P[left]  {}\mRightarrow{}  P[right]  {}\mRightarrow{}  P[tree\_node(left;right)]))
    {}\mRightarrow{}  \{\mforall{}v:tree(E).  P[v]\})
Date html generated:
2017_10_01-AM-08_30_33
Last ObjectModification:
2017_07_26-PM-04_24_38
Theory : tree_1
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