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: 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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