People are strolling across some stores.
The people are window-shopping.
Window-shopping is a specific act, where as sometimes people are just passing by.
exists e1 x1 x2.(across(e1,x2) & n_store(x2) & Actor(e1,x1) & v_stroll(e1) & n_people(x1))
exists s1 x1.(n_people(x1) & Theme(s1,x1) & a_window-shopping(s1))