Mathnificent Word of the Week

Originally posted on
April 4, 2023

affine

Photo by Grace Ho on Unsplash

affine

/ɘ-’fīn/

adjective

Allowing for or preserving parallel relationships.

“Carmen created affine groups within her company so that any future organizational shifts would, in theory, automatically balance out across the board.”

Photo by Grace Ho on Unsplash

I think you’re gonna be more than (af)fine with affine.

You don’t need to read the most recent KLM* essay on Self-Similarity to get the full shah-POW of this MWFYW but, dang, I didn’t know about the math-world definition of affine or affinity which then leads to self-affinity till I was doing my research for that essay cuz, wow — they are totally related.

In geometry, according to Mandelbrot (our grandaddy of fractals), self-similarity is the carbon-copy action of “shapes scaling by the same amount in every direction.”

Affine – and onward to affinity then to self-affinity – is just like self-similarity but the carbon-copy action has those shapes scaling in different amounts in only some of its directions. Mandelbrot referred to self-affinity as turbulence.

Self-affinity is turbulent self-similarity.
Now, take my hand (no need to squeeze that hard, sweetie, we’re just talking about mathematics) and let’s look at what’s probably a more familiar usage of this Math WoW for you, as exemplified in this sentence, “I have such an affinity for confident nerds.” Here, affinity means having a particular liking for something or, more often, for a person or people. We commonly use the word affinity in a relational context.

Just as applying self-similarity to real life uncovers how long term processes & systems can arise biases within, self-affinity may be just the thing – that good version of self-similarity – that I was looking for.

A group that has self-affinity rather than self-similarity would be one that has experienced turbulence within as it does that carbon-copy action of scaling. As ‘they’ say , whether you’re part of a couple or a group of people – long-term healthy relationships have disagreements; that’s definitely a type of turbulence.

Groups transform over time – sometimes scaling up and sometimes scaling down. With self-affinity, if you’re realistic about wanting to ensure long term sustainability of that relationship or group, that scaling actually doesn’t – and shouldn’t – scale equally every step of the way.

Huh. Where have you been all my life, affine?


Other Math Words of the Week