let S be locally_directed OrderSortedSign; :: thesis: for X being V5() ManySortedSet of
for o being OperSymbol of S
for x being FinSequence of TS (DTConOSA X) holds
( LeastSorts x <= the_arity_of o iff x in Args o,(ParsedTermsOSA X) )

let X be V5() ManySortedSet of ; :: thesis: for o being OperSymbol of S
for x being FinSequence of TS (DTConOSA X) holds
( LeastSorts x <= the_arity_of o iff x in Args o,(ParsedTermsOSA X) )

let o be OperSymbol of S; :: thesis: for x being FinSequence of TS (DTConOSA X) holds
( LeastSorts x <= the_arity_of o iff x in Args o,(ParsedTermsOSA X) )

let x be FinSequence of TS (DTConOSA X); :: thesis: ( LeastSorts x <= the_arity_of o iff x in Args o,(ParsedTermsOSA X) )
set PTA = ParsedTermsOSA X;
set D = DTConOSA X;
set w = the_arity_of o;
set LSx = LeastSorts x;
A1: ( dom (LeastSorts x) = dom x & ( for y being Nat st y in dom x holds
ex t being Element of TS (DTConOSA X) st
( t = x . y & (LeastSorts x) . y = LeastSort t ) ) ) by Def14;
reconsider SPTA = the Sorts of (ParsedTermsOSA X) as OrderSortedSet of ;
hereby :: thesis: ( x in Args o,(ParsedTermsOSA X) implies LeastSorts x <= the_arity_of o )
assume A2: LeastSorts x <= the_arity_of o ; :: thesis: x in Args o,(ParsedTermsOSA X)
then ( len (LeastSorts x) = len (the_arity_of o) & ( for i being set st i in dom (LeastSorts x) holds
for s1, s2 being Element of S st s1 = (LeastSorts x) . i & s2 = (the_arity_of o) . i holds
s1 <= s2 ) ) by OSALG_1:def 7;
then A3: ( dom (LeastSorts x) = dom (the_arity_of o) & len x = len (the_arity_of o) ) by A1, FINSEQ_3:31;
for k being Nat st k in dom x holds
x . k in the Sorts of (ParsedTermsOSA X) . ((the_arity_of o) /. k)
proof
let k be Nat; :: thesis: ( k in dom x implies x . k in the Sorts of (ParsedTermsOSA X) . ((the_arity_of o) /. k) )
assume A4: k in dom x ; :: thesis: x . k in the Sorts of (ParsedTermsOSA X) . ((the_arity_of o) /. k)
A5: (the_arity_of o) /. k = (the_arity_of o) . k by A1, A3, A4, PARTFUN1:def 8;
reconsider wk = (the_arity_of o) /. k as Element of S ;
consider t2 being Element of TS (DTConOSA X) such that
A6: ( t2 = x . k & (LeastSorts x) . k = LeastSort t2 ) by A4, Def14;
A7: t2 in the Sorts of (ParsedTermsOSA X) . (LeastSort t2) by Def12;
LeastSort t2 <= wk by A1, A2, A4, A5, A6, OSALG_1:def 7;
then SPTA . (LeastSort t2) c= SPTA . wk by OSALG_1:def 18;
hence x . k in the Sorts of (ParsedTermsOSA X) . ((the_arity_of o) /. k) by A6, A7; :: thesis: verum
end;
hence x in Args o,(ParsedTermsOSA X) by A3, MSAFREE2:7; :: thesis: verum
end;
assume A8: x in Args o,(ParsedTermsOSA X) ; :: thesis: LeastSorts x <= the_arity_of o
then A9: ( dom x = dom (the_arity_of o) & ( for i being Nat st i in dom (the_arity_of o) holds
x . i in the Sorts of (ParsedTermsOSA X) . ((the_arity_of o) /. i) ) ) by MSUALG_6:2;
hence len (LeastSorts x) = len (the_arity_of o) by A1, FINSEQ_3:31; :: according to OSALG_1:def 7 :: thesis: for b1 being set holds
( not b1 in dom (LeastSorts x) or for b2, b3 being Element of the carrier of S holds
( not b2 = (LeastSorts x) . b1 or not b3 = (the_arity_of o) . b1 or b2 <= b3 ) )

let i be set ; :: thesis: ( not i in dom (LeastSorts x) or for b1, b2 being Element of the carrier of S holds
( not b1 = (LeastSorts x) . i or not b2 = (the_arity_of o) . i or b1 <= b2 ) )

assume A10: i in dom (LeastSorts x) ; :: thesis: for b1, b2 being Element of the carrier of S holds
( not b1 = (LeastSorts x) . i or not b2 = (the_arity_of o) . i or b1 <= b2 )

A11: ( i in dom (the_arity_of o) & i in dom x ) by A9, A10, Def14;
reconsider k = i as Nat by A10;
let s1, s2 be Element of S; :: thesis: ( not s1 = (LeastSorts x) . i or not s2 = (the_arity_of o) . i or s1 <= s2 )
assume A12: ( s1 = (LeastSorts x) . i & s2 = (the_arity_of o) . i ) ; :: thesis: s1 <= s2
consider t2 being Element of TS (DTConOSA X) such that
A13: ( t2 = x . k & (LeastSorts x) . k = LeastSort t2 ) by A11, Def14;
A14: (the_arity_of o) /. k = (the_arity_of o) . k by A1, A9, A10, PARTFUN1:def 8;
x . k in the Sorts of (ParsedTermsOSA X) . ((the_arity_of o) /. k) by A8, A11, MSUALG_6:2;
hence s1 <= s2 by A12, A13, A14, Def12; :: thesis: verum