NTerms[x] is equivalent to Length if x is a sum; otherwise NTerms[x] returns 1, except NTerms[0] -> 0.
![[Graphics:Images/index_gr_1.gif]](Images/index_gr_1.gif)
![[Graphics:Images/index_gr_2.gif]](Images/index_gr_2.gif){kind=small}
![[Graphics:Images/index_gr_3.gif]](Images/index_gr_3.gif)
![[Graphics:Images/index_gr_4.gif]](Images/index_gr_4.gif){kind=small}
![[Graphics:Images/index_gr_5.gif]](Images/index_gr_5.gif)
![[Graphics:Images/index_gr_6.gif]](Images/index_gr_6.gif){kind=small}
![[Graphics:Images/index_gr_7.gif]](Images/index_gr_7.gif)
Nielsen
OneLoop![[Graphics:Images/index_gr_8.gif]](Images/index_gr_8.gif){kind=small}