let L be non trivial Polish-language; for E being Polish-arity-function of L
for t being Element of L st E . t = 1 holds
for F being Polish-WFF of L,E st Polish-WFF-head F = t holds
ex G being Polish-WFF of L,E st F = (Polish-unOp (L,E,t)) . G
let E be Polish-arity-function of L; for t being Element of L st E . t = 1 holds
for F being Polish-WFF of L,E st Polish-WFF-head F = t holds
ex G being Polish-WFF of L,E st F = (Polish-unOp (L,E,t)) . G
let t be Element of L; ( E . t = 1 implies for F being Polish-WFF of L,E st Polish-WFF-head F = t holds
ex G being Polish-WFF of L,E st F = (Polish-unOp (L,E,t)) . G )
assume A1:
E . t = 1
; for F being Polish-WFF of L,E st Polish-WFF-head F = t holds
ex G being Polish-WFF of L,E st F = (Polish-unOp (L,E,t)) . G
let F be Polish-WFF of L,E; ( Polish-WFF-head F = t implies ex G being Polish-WFF of L,E st F = (Polish-unOp (L,E,t)) . G )
assume A2:
Polish-WFF-head F = t
; ex G being Polish-WFF of L,E st F = (Polish-unOp (L,E,t)) . G
consider u being Element of (Polish-WFF-set (L,E)) ^^ 1 such that
A3:
F = (Polish-operation (L,E,t)) . u
by A1, A2, Th79;
reconsider G = u as Polish-WFF of L,E ;
take
G
; F = (Polish-unOp (L,E,t)) . G
thus
F = (Polish-unOp (L,E,t)) . G
by A1, A3, Def27; verum