Rank-one connection
= Rank-one connection
{title2=$A-B=a\otimes N$}
Two constant <deformation gradients> are rank-one connected when their difference is an <outer product> $a\otimes N$. For a nonzero jump its <matrix rank> is one; equality $A=B$ is the trivial compatible case. The vector $N$ specifies a reference interface normal, and $a$ is the jump amplitude. The <Hadamard jump condition> identifies this algebraic condition with continuity of an affine deformation across a planar interface. The normal can be normalized by rescaling $a$ without changing the product.