Lm22:
for x being trivial set
for y being Subset of x st not y is empty holds
x = y
Lemma1:
for B being Polish-arity-function holds
( B is empty-yielding iff for a being object st a in dom B holds
B . a = 0 )
Lm2:
for K being non trivial Polish-language
for m, n being Nat
for a being object st a in K ^^ m & a in K ^^ n holds
m <= n
Lm3:
for T being Polish-language
for m, n being Nat
for a being object st a in T ^^ m & a in T ^^ n & not T is trivial holds
m = n
Lm4:
for T being Polish-language
for A being Polish-arity-function of T
for t being Element of T
for u being FinSequence holds
( t ^ u in Polish-WFF-set (T,A) iff u in (Polish-WFF-set (T,A)) ^^ (A . t) )
Lm5:
for T being Polish-language
for A being Polish-arity-function of T
for a being object st T is trivial & a in T holds
A . a = 0
Lm21:
for B being Polish-arity-function
for J being Polish-ext-set of B
for a being object st a in Polish-ext-complement (B,J) holds
( a in J & a in Polish-ext-domain (B,J) & not a in dom B )
Lm23:
for B being Polish-arity-function
for J being Polish-ext-set of B st ( {} in J or {} in dom B ) holds
( J = {{}} & Polish-WFF-set B = {{}} & dom B = {{}} & Polish-ext-complement (B,J) = {} )
Lm19:
for P being non empty FinSequence-membered set
for p being FinSequence
for n being Nat holds
( p in P |` n iff ( p in P & len p <= n ) )
Lm20:
for P being non empty FinSequence-membered set
for m, n being Nat holds (P ^^ n) |` m c= (P |` m) ^^ n
Lm9:
for T being Polish-language
for A being Polish-arity-function of T st A is empty-yielding holds
Polish-WFF-set (T,A) = T