theorem Th149: :: SHEFFER2:149

for L being non empty satisfying_Sheffer_1 satisfying_Sheffer_2 satisfying_Sheffer_3 ShefferStr
for p, z, y, x being Element of L holds ((z | (x | p)) | (z | (x | p))) | (((x | (y | (y | y))) | z) | ((p | p) | z)) = (((p | p) | z) | ((x | (y | (y | y))) | z)) | (((p | p) | z) | ((x | (y | (y | y))) | z))