The orientation of the dual bonds must be such that the vector product between each bond and its dual bond has the same sign with respect to the normal versor outgoing from the surface.
General duality for abelian-group-valued statistical-mechanics models
We call e(i) the versors of the canonical basis of Rd .
Which random walks are cyclic?
The last direction - side - is along the vector product of the out and long versors.
Test of Bowler-Sinyukov Treatment of Coulomb Interaction
The operators appearing in (3) are the orbital ~L and spin ~S angular momenta, the position versor br = ~r/r, and the spin-transition operator ~T deﬁned here as the spin analog of br (see sect. 2.4 below for a detailed discussion of this operator).
Addition theorems for spin spherical harmonics. I Preliminaries
As in the previous case, the product of standard versors can be substituted by δkh .
Addition theorems for spin spherical harmonics. I Preliminaries
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