Nice analysis; I’ve been meaning to learn Coq and this seems like a good introduction.

]]>In short, the equality “k = b” holds by transitivity with “kk”; the two equations (a) “k = kk” and (b) “kk = b” only require that (a) k is fond of k and (b) k is fixated on b (to be sure, a stronger claim than “kk = b,” but one given by the egocentricity of a self-fond kestrel). No kestrel properties required.

That parenthetical took me some time to wrap my brain around: a self-fond kestrel k is egocentric as shown, but this implies that k is fixated on any bird b! Egocentricity gives “kb = k,” but replace “k is fixated with b” with “kb is fixated with b” which is equivalent to “k is a kestrel”!

https://github.com/benknoble/junk-drawer/blob/master/code/mockingbirds.v, esp. https://github.com/benknoble/junk-drawer/blob/aad6a93e52cf717b6d78a48f9c366402f70e329f/code/mockingbirds.v#L72

]]>Yes, I think this is a good path to understanding it, thanks. I’ll have to read it a couple of additional times though. Thank you for spending time explaining!

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