let V be set ; for G being Graph
for v1, v2 being Element of G holds AcyclicPaths (v1,v2,V) c= AcyclicPaths G
let G be Graph; for v1, v2 being Element of G holds AcyclicPaths (v1,v2,V) c= AcyclicPaths G
let v1, v2 be Element of G; AcyclicPaths (v1,v2,V) c= AcyclicPaths G
let e be set ; TARSKI:def 3 ( not e in AcyclicPaths (v1,v2,V) or e in AcyclicPaths G )
assume
e in AcyclicPaths (v1,v2,V)
; e in AcyclicPaths G
then
ex q being oriented Simple Chain of G st
( e = q & q is_acyclicpath_of v1,v2,V )
;
hence
e in AcyclicPaths G
; verum