let IIG be non empty finite non void Circuit-like monotonic ManySortedSign ; :: thesis: for SCS being non-empty Circuit of IIG
for InpFs being InputFuncs of SCS st commute InpFs is constant & not InputVertices IIG is empty holds
for s being State of SCS
for iv being InputValues of SCS st iv = (commute InpFs) . 0 holds
for k being Element of NAT
for v being Vertex of IIG st depth v,SCS <= k holds
((Computation s,InpFs) . k) . v = IGValue v,iv

let SCS be non-empty Circuit of IIG; :: thesis: for InpFs being InputFuncs of SCS st commute InpFs is constant & not InputVertices IIG is empty holds
for s being State of SCS
for iv being InputValues of SCS st iv = (commute InpFs) . 0 holds
for k being Element of NAT
for v being Vertex of IIG st depth v,SCS <= k holds
((Computation s,InpFs) . k) . v = IGValue v,iv

let InpFs be InputFuncs of SCS; :: thesis: ( commute InpFs is constant & not InputVertices IIG is empty implies for s being State of SCS
for iv being InputValues of SCS st iv = (commute InpFs) . 0 holds
for k being Element of NAT
for v being Vertex of IIG st depth v,SCS <= k holds
((Computation s,InpFs) . k) . v = IGValue v,iv )

assume A1: ( commute InpFs is constant & not InputVertices IIG is empty ) ; :: thesis: for s being State of SCS
for iv being InputValues of SCS st iv = (commute InpFs) . 0 holds
for k being Element of NAT
for v being Vertex of IIG st depth v,SCS <= k holds
((Computation s,InpFs) . k) . v = IGValue v,iv

then A2: IIG is with_input_V by MSAFREE2:def 4;
let s be State of SCS; :: thesis: for iv being InputValues of SCS st iv = (commute InpFs) . 0 holds
for k being Element of NAT
for v being Vertex of IIG st depth v,SCS <= k holds
((Computation s,InpFs) . k) . v = IGValue v,iv

let iv be InputValues of SCS; :: thesis: ( iv = (commute InpFs) . 0 implies for k being Element of NAT
for v being Vertex of IIG st depth v,SCS <= k holds
((Computation s,InpFs) . k) . v = IGValue v,iv )

assume A3: iv = (commute InpFs) . 0 ; :: thesis: for k being Element of NAT
for v being Vertex of IIG st depth v,SCS <= k holds
((Computation s,InpFs) . k) . v = IGValue v,iv

defpred S1[ Element of NAT ] means for v being Vertex of IIG st depth v,SCS <= $1 holds
((Computation s,InpFs) . $1) . v = IGValue v,iv;
A4: S1[ 0 ]
proof
let v be Vertex of IIG; :: thesis: ( depth v,SCS <= 0 implies ((Computation s,InpFs) . 0 ) . v = IGValue v,iv )
assume depth v,SCS <= 0 ; :: thesis: ((Computation s,InpFs) . 0 ) . v = IGValue v,iv
then A5: depth v,SCS = 0 by NAT_1:3;
A6: (Computation s,InpFs) . 0 = InitialComp s,InpFs by Def9
.= (s +* (0 -th_InputValues InpFs)) +* (Set-Constants SCS) ;
per cases ( v in InputVertices IIG or v in SortsWithConstants IIG ) by A5, CIRCUIT1:19;
end;
end;
A11: for k being Element of NAT st S1[k] holds
S1[k + 1]
proof
let k be Element of NAT ; :: thesis: ( S1[k] implies S1[k + 1] )
reconsider Ck = (Computation s,InpFs) . k as State of SCS ;
assume A12: S1[k] ; :: thesis: S1[k + 1]
A13: dom (commute InpFs) = NAT by A1, PRE_CIRC:8;
A14: (k + 1) -th_InputValues InpFs = (commute InpFs) . (k + 1) by A2, CIRCUIT1:def 2
.= (commute InpFs) . 0 by A1, A13, FUNCT_1:def 16 ;
A15: iv c= Ck by A1, A3, Th14;
let v be Vertex of IIG; :: thesis: ( depth v,SCS <= k + 1 implies ((Computation s,InpFs) . (k + 1)) . v = IGValue v,iv )
assume A16: depth v,SCS <= k + 1 ; :: thesis: ((Computation s,InpFs) . (k + 1)) . v = IGValue v,iv
thus ((Computation s,InpFs) . (k + 1)) . v = (Following Ck,((k + 1) -th_InputValues InpFs)) . v by Def9
.= (Following Ck) . v by A3, A14, A15, FUNCT_4:79
.= IGValue v,iv by A12, A16, Th13 ; :: thesis: verum
end;
thus for k being Element of NAT holds S1[k] from NAT_1:sch 1(A4, A11); :: thesis: verum