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What is the generic name for these triangles where you can "select any two" but never have all three?


A trilemma.


The list on Wikipedia is pretty neat: https://en.wikipedia.org/wiki/Trilemma

> One of the earliest uses of the trilemma formulation is that of the Greek philosopher Epicurus, rejecting the idea of an omnipotent and omnibenevolent god (as summarised by David Hume).


This is absolutely hilarious and made me laugh really hard for some reason. Thanks. I'm using this term forever.


https://en.wikipedia.org/wiki/Trilemma

Coined in the 1600s, most likely. Can be used one of two ways:

1. A choice between 3 unfavorable options where you must choose one (lose your arm, your leg, or your other arm).

2. A choice between 3 favorable options where you can only choose two (the typical ones we see discussed/posted here).


One can observe that the first is a special case of the second, through the transformation of negation ("choose which two of your arm, your leg or your other arm to keep"). We can unify both under this system.


Negation works both ways, so it's not that one is a special case of the other; instead, they're simply equivalent.


Right. The normal way we see it written here, like with the CAP theorem, would be:

  CA~P + C~AP + ~CAP
The way it's normally phrased would be: choose 2 of the 3 that you want, the other will be absent from your system. The alternate phrasing would be: choose 1 of the 3 that you can sacrifice, the others will be present in your system. But both phrasings describe the same logical expression written above.

For the right arm, left arm, leg example it's similar. You're being asked which one you would sacrifice so it could be written as:

  RA LA ~L + RA ~LA L + ~RA LA L
Offering two phrasings: which do you want to keep or which will you give up?


"StavrosK's triangle".


Who is to say that it isn't? If only we had a secure, decentralized system for mapping human-meaningful names to things...




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