Analysing knots and ligatures: Tying principles, knot characteristics and structural changes

Homicides and suicides involving ligatures, and accidents resulting from failed safety systems, sometimes necessitate the careful analysis of knots. Aside from performing accurate knot identifications, establishing knot chirality, and determining whether those knots are commonplace or require specialised training, the experienced analyst evaluates various knot characteristics and is guided by underlying principles and evolving standards, which draw on multiple disciplines. These include the Gordian Maxim as well as the efficiency, ownership and parsimony principles. Subsequent to distinguishing between accidental and deliberate knots, an assessment of knot structure, function and effectiveness sometimes necessitates an understanding of Ashley's principle and Asher's law. Crossing number, writhe, strength, security and concatenation can be valuable analysis characteristics. Knot stability may be evaluated using established counting number algorithms. Methods of determining sinuosity and knottability are useful as well. Knots occur with structural variation and they can change accidentally or through deliberate action. Capsizement, flipping, flyping, migration, release, reptation, trambling, transference and enhancement are knot change processes. Along with tier behaviour and material characteristics, these details may require assessment during evidence analysis.