Nuprl Lemma : lg-acyclic-has-source
∀[T:Type]. ∀g:LabeledGraph(T). (∃i:ℕlg-size(g). (↑lg-is-source(g;i))) supposing (lg-acyclic(g) and 0 < lg-size(g))
Proof
Definitions occuring in Statement : 
lg-is-source: lg-is-source(g;i)
, 
lg-acyclic: lg-acyclic(g)
, 
lg-size: lg-size(g)
, 
labeled-graph: LabeledGraph(T)
, 
int_seg: {i..j-}
, 
assert: ↑b
, 
less_than: a < b
, 
uimplies: b supposing a
, 
uall: ∀[x:A]. B[x]
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
natural_number: $n
, 
universe: Type
Lemmas : 
int_seg_wf, 
lg-size_wf, 
exists_wf, 
lg-edge_wf, 
all_wf, 
nat_wf, 
equal_wf, 
nat_plus_properties, 
lg-connected_wf, 
fun_exp_wf, 
zero-le-nat, 
le_wf, 
false_wf, 
lelt_wf, 
primrec-wf-nat-plus, 
nat_plus_wf, 
lg-edge-lg-connected, 
decidable__le, 
not-le-2, 
sq_stable__le, 
condition-implies-le, 
minus-add, 
minus-one-mul, 
zero-add, 
add-associates, 
add-swap, 
add-commutes, 
add_functionality_wrt_le, 
add-zero, 
le-add-cancel, 
fun_exp_add1, 
lg-connected_transitivity, 
subtype_base_sq, 
int_subtype_base, 
pigeon-hole-implies, 
less-iff-le, 
decidable__lt, 
add-mul-special, 
zero-mul, 
int_seg_subtype-nat, 
sq_stable__equal, 
subtract_wf, 
less_than_transitivity2, 
le_weakening2, 
less_than_irreflexivity, 
less_than_wf
Latex:
\mforall{}[T:Type]
    \mforall{}g:LabeledGraph(T)
        (\mexists{}i:\mBbbN{}lg-size(g).  (\muparrow{}lg-is-source(g;i)))  supposing  (lg-acyclic(g)  and  0  <  lg-size(g))
Date html generated:
2015_07_22-PM-00_29_35
Last ObjectModification:
2015_01_28-PM-11_35_18
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