consider z being non empty set ;
consider z1 being Element of z;
take
TrivialOSA (S,z,z1)
; ( TrivialOSA (S,z,z1) is monotone & TrivialOSA (S,z,z1) is strict & TrivialOSA (S,z,z1) is non-empty )
thus
( TrivialOSA (S,z,z1) is monotone & TrivialOSA (S,z,z1) is strict & TrivialOSA (S,z,z1) is non-empty )
by Th29; verum