hi,

i'm doing project on robotics...and i've some equations to be considered.... i'm not well in maths.. can you explain the conditions given in eqn like [2], [4] & [6] in the attachment below...something like scalar product and set of vectors in half plane... but sure can you clarify or point me direction...

thx in advance...

http://www.ensieta.fr/jaulin/paper_k...iable_comp.pdf