[vitiral]

I'm familiar with bras I think... what is a "ket"?

[hprotagonist]

https://en.wikipedia.org/wiki/Bra%E2%80%93ket_notation

a ket is |v>

[vitiral]

It seems I was NOT familiar with what a bra is...

[NiceKeeb]

It's the hermitian conjugate of the corresponding ket.

[HideousKojima]

And a monad is an endofunctor of a monoid

[vitiral]

With that at least I can be nearly certain we are not discussing an alternative brassiere.

[capitalsigma]

It's physicist notation for inner products: https://en.wikipedia.org/wiki/Bra%E2%80%93ket_notation