Where does composite collide?

In number theory a composite number is a positive integer greater than 1 that is not prime, meaning it can be written as a product of smaller positive integers and so has divisors besides 1 and itself. Euclid's Elements defines the composite number in its arithmetical books and builds the theory of primes and factorisation around the distinction. The referent is a precise property of an integer, defined by divisibility, and has nothing to do with a blended photograph or an engineered material beyond the shared root meaning of being put together from parts.[1]

Unit

An integer greater than 1 that has a divisor other than 1 and itself

Recovery means

Not applicable

Measured by

Established by exhibiting a nontrivial factorisation, or by a primality test that the number fails

In nineteenth-century anthropometry a composite portrait is a single picture produced by optically superimposing many individual photographs, so that shared features reinforce and idiosyncratic ones fade, yielding an averaged face. Galton's 1879 Composite portraits, made by combining those of many different persons into a single resultant figure introduced the technique as a way to depict a supposed type. The referent is a blended, averaged image made by overlaying many originals, an entirely different object from a non-prime integer or a reinforced engineering material, joined only by the idea of combining many into one.[2]

Unit

A single averaged image synthesised from many overlaid photographs

Recovery means

Not applicable

Measured by

Produced and compared by the number of exposures overlaid and the resulting averaged features