let IIG be non empty non void Circuit-like monotonic ManySortedSign ; for SCS being non-empty Circuit of IIG
for v being Vertex of IIG
for iv being InputValues of SCS holds IGTree (v,iv) = ((Fix_inp_ext iv) . v) . (IGTree (v,iv))
let SCS be non-empty Circuit of IIG; for v being Vertex of IIG
for iv being InputValues of SCS holds IGTree (v,iv) = ((Fix_inp_ext iv) . v) . (IGTree (v,iv))
let v be Vertex of IIG; for iv being InputValues of SCS holds IGTree (v,iv) = ((Fix_inp_ext iv) . v) . (IGTree (v,iv))
let iv be InputValues of SCS; IGTree (v,iv) = ((Fix_inp_ext iv) . v) . (IGTree (v,iv))
reconsider igt = IGTree (v,iv) as Element of the Sorts of (FreeEnv SCS) . v ;
ex e being Element of the Sorts of (FreeEnv SCS) . v st
( card e = size (v,SCS) & IGTree (v,iv) = ((Fix_inp_ext iv) . v) . e )
by Def3;
then
card igt = size (v,SCS)
by Th7;
hence
IGTree (v,iv) = ((Fix_inp_ext iv) . v) . (IGTree (v,iv))
by Def3; verum