a cyclist
There is no such thing as a cyclist
A cyclist standing alone implies a noun, to say that there is no such thing takes away the implicit meaning of a standalone phrase.
exists x1.(a_topic(x1) & n_cyclist(x1))
exists p1 x1.-exists s1 x2 x3.((x1 = x2) & as(x2,x3) & n_cyclist(x3) & n_thing(x2) & a_such(s1) & Theme(s1,x2))