Items are being sold in the open market by it's vendors.
The vendors are manning their booths.
The fact that items are sold by vendors at the market doesn't imply the vendors are manning their booths.
exists e1 p1 s1 x1 x2 x3.(n_thing(x2) & n_market(x2) & a_open(s1) & Theme(s1,x2) & Actor(e1,x2) & exists x4.((x3 = x4) & n_vendor(x4)) & (x2 = x3) & in(e1,x2) & Theme(e1,x1) & v_sell(e1) & n_item(x1))
exists e1 x1 x2.(n_booth(x2) & of(x2,x1) & n_thing(x1) & n_vendor(x1) & Theme(e1,x2) & Actor(e1,x1) & v_man(e1))