The man wearing a blue helmet is riding a Polaris.
A man rides a Polaris.
Riding is the passive form of rides.
exists e2 e1 s1 x1 x2 x3 x4.(n_man(x1) & Theme(e2,x4) & Actor(e2,x1) & v_ride(e2) & ne_org_polaris(x4) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & n_helmet(x3) & a_blue(s1) & Theme(s1,x3) & (x1 = x2))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & ne_org_polaris(x2) & n_man(x1))