in three (or possibly two) dimensions
along: a curve in three (or possibly two) dimensions
of: a vector quantity 
that depends on position and is defined at all points on
is given: by
where: 
is a small displacement along 
and the sum is over a sequence of small displacements that lead from A to B along 
Note that in this definition 
represents a scalar product. [P2.4]
Copyright 1997, The Open University