set R = the BinOp of {{}};
take
TopGrStr(# {{}}, the BinOp of {{}},(bool {{}}) #)
; ( TopGrStr(# {{}}, the BinOp of {{}},(bool {{}}) #) is strict & TopGrStr(# {{}}, the BinOp of {{}},(bool {{}}) #) is TopSpace-like & TopGrStr(# {{}}, the BinOp of {{}},(bool {{}}) #) is 1 -element )
the carrier of (1TopSp {{}}) is 1 -element
;
hence
( TopGrStr(# {{}}, the BinOp of {{}},(bool {{}}) #) is strict & TopGrStr(# {{}}, the BinOp of {{}},(bool {{}}) #) is TopSpace-like & TopGrStr(# {{}}, the BinOp of {{}},(bool {{}}) #) is 1 -element )
by TEX_2:7; verum