let IIG be non empty non void Circuit-like monotonic ManySortedSign ; :: thesis: for A being non-empty Circuit of IIG
for v being Vertex of IIG holds
( depth v,A = 0 iff ( v in InputVertices IIG or v in SortsWithConstants IIG ) )

let A be non-empty Circuit of IIG; :: thesis: for v being Vertex of IIG holds
( depth v,A = 0 iff ( v in InputVertices IIG or v in SortsWithConstants IIG ) )

let v be Vertex of IIG; :: thesis: ( depth v,A = 0 iff ( v in InputVertices IIG or v in SortsWithConstants IIG ) )
consider s being non empty finite Subset of NAT such that
A1: s = { (depth t) where t is Element of the Sorts of (FreeEnv A) . v : verum } and
A2: depth v,A = max s by Def6;
reconsider Y = s as non empty finite real-membered set ;
max Y in { (depth t) where t is Element of the Sorts of (FreeEnv A) . v : verum } by A1, XXREAL_2:def 8;
then consider t being Element of the Sorts of (FreeEnv A) . v such that
A3: depth t = max Y ;
consider t2 being Element of the Sorts of (FreeMSA the Sorts of A) . v such that
A4: t = t2 and
A5: depth t = depth t2 by Def5;
consider dt being finite DecoratedTree, t' being finite Tree such that
A6: dt = t2 and
A7: t' = dom dt and
A8: depth t2 = height t' by MSAFREE2:def 14;
consider p being FinSequence of NAT such that
A9: p in t' and
A10: len p = height t' by TREES_1:def 15;
consider ss being non empty finite Subset of NAT such that
A11: ss = { (card tt) where tt is Element of the Sorts of (FreeEnv A) . v : verum } and
A12: size v,A = max ss by Def4;
reconsider YY = ss as non empty finite real-membered set ;
reconsider t'' = t as Function ;
thus ( not depth v,A = 0 or v in InputVertices IIG or v in SortsWithConstants IIG ) :: thesis: ( ( v in InputVertices IIG or v in SortsWithConstants IIG ) implies depth v,A = 0 )
proof
assume A13: depth v,A = 0 ; :: thesis: ( v in InputVertices IIG or v in SortsWithConstants IIG )
then rng t'' = {(t . {} )} by A2, A3, A4, A5, A6, A7, A8, FUNCT_1:14, TREES_1:56, TREES_1:80;
then t'' = {[{} ,(t . {} )]} by A2, A3, A4, A5, A6, A7, A8, A13, PRE_CIRC:2, TREES_1:56, TREES_1:80;
then card t = 1 by CARD_1:50;
then A14: 1 in YY by A11;
for kk being ext-real number st kk in YY holds
kk <= 1
proof
let kk be ext-real number ; :: thesis: ( kk in YY implies kk <= 1 )
assume kk in YY ; :: thesis: kk <= 1
then consider tt being Element of the Sorts of (FreeEnv A) . v such that
A15: card tt = kk by A11;
depth tt in Y by A1;
then depth tt <= 0 by A2, A13, XXREAL_2:def 8;
then A16: depth tt = 0 ;
consider tiv being Element of the Sorts of (FreeMSA the Sorts of A) . v such that
A17: tt = tiv and
A18: depth tt = depth tiv by Def5;
consider dt' being finite DecoratedTree, t''' being finite Tree such that
A19: dt' = tiv and
A20: t''' = dom dt' and
A21: depth tiv = height t''' by MSAFREE2:def 14;
rng tt = {(tt . {} )} by A16, A17, A18, A19, A20, A21, FUNCT_1:14, TREES_1:56, TREES_1:80;
then tt = {[{} ,(tt . {} )]} by A16, A17, A18, A19, A20, A21, PRE_CIRC:2, TREES_1:56, TREES_1:80;
hence kk <= 1 by A15, CARD_1:50; :: thesis: verum
end;
then size v,A = 1 by A12, A14, XXREAL_2:def 8;
then v in (InputVertices IIG) \/ (SortsWithConstants IIG) by Th11;
hence ( v in InputVertices IIG or v in SortsWithConstants IIG ) by XBOOLE_0:def 3; :: thesis: verum
end;
assume ( v in InputVertices IIG or v in SortsWithConstants IIG ) ; :: thesis: depth v,A = 0
then v in (InputVertices IIG) \/ (SortsWithConstants IIG) by XBOOLE_0:def 3;
then A22: size v,A = 1 by Th11;
A23: card t in ss by A11;
card t in NAT ;
then reconsider ct = card t as Real ;
ct <= 1 by A12, A22, A23, XXREAL_2:def 8;
then A24: ( card t <= 0 or card t = 0 + 1 ) by NAT_1:8;
consider x being set such that
A25: t = {x} by A24, CARD_2:60;
{} in dom t by TREES_1:47;
then consider y being set such that
A26: [{} ,y] in t'' by RELAT_1:def 4;
A27: x = [{} ,y] by A25, A26, TARSKI:def 1;
consider y'' being set such that
A28: [p,y''] in t'' by A4, A6, A7, A9, RELAT_1:def 4;
[p,y''] = [{} ,y] by A25, A27, A28, TARSKI:def 1;
then p = {} by ZFMISC_1:33;
hence depth v,A = 0 by A2, A3, A5, A8, A10; :: thesis: verum