\omega \left (V_0, \ldots, \hat V_i, \ldots,V_k \right ) = \omega \left (V_0, \ldots, V_{i-1}, V_{i+1}, \ldots, V_k \right ).
In particular, for 1-forms we have: , where and are vector fields, is the scalar field defined by the vector field applied as a differential operator ("directional derivative along X") to the scalar field defined by applying as a covector field to the vector field and likewise for .