theorem Th114: :: SHEFFER2:114

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