• affiliate@lemmy.world
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    13 days ago

    i also think the “etymology” of the boolean symbols is very helpful in remembering which is which. in lattice theory, their use was inspired by similar notation in set theory. so, AB is like AB, while AB is like AB.

    generally, AB is “the smallest thing that’s greater than or equal to both A and B”, while AB is “the biggest thing that’s less than or equal to both A and B”. similarly to how AB is “the smallest set that contains both A and B”, while AB is “the largest set that’s contained in both A and B”. you can also take things a step further by saying that in the context of sets, AB means AB. doing this means that A ∨ B = A ∪ B, while A ∧ B = A ∩ B. and from this perspective, the “sharp-edged” symbols (<, , ) are just a generalization of their “curvy” counterparts (, , ).

    in the context of boolean algebra, you can set False < True, which at first may seem a bit arbitrary, but it agrees with the convention the that False = 0 and True = 1, and it also makes AB and AB have the same meanings as described above.