Today, 71 years ago, on October 16, 1954 (Calendar, September 20, 1954), YU PINGPING published a letter on the study of the dream of the red building. YU PINGPINGPING, a red scientist, then professor at the University of Beijing in 1954, said: "This is the first seriously open fire to the misconception of the authoritative writers of the so-called red building research authority for more than thirty years"; "It is the two 'little people' are done, and the 'big people' are often ignored and often blocked, and they are willing to be the prisoners of the red class with the bourgeois writers in the unification of the line of battle with the ideology of the red building and the bourgeoisie."