[ossopite]

ROT13

Fb V guvax gur nafjre eribyirf nebhaq gur pbzcbfvgvba ynj. Va bgure jbeqf, vf sznc (sznc frg s) t rdhny gb sznc frg (t . s) sbe nal s naq t?

V guvax guvf ubyqf bayl vs s naq t ner cher (be znlor whfg vs t vf cher?). fb znlor vs lbh vtaber hafnsr bcrengvbaf va unfxryy vg'f gehr? vg'f pregnvayl abg gehr va s#/bpnzy. vzntvar gung s vf sha _ -> 0 naq t vf sha _ -> arkg_vag_sebz_zhgnoyr_pbhagre (). gura sznc frg (t . s) qbrfa'g punatr gur fvmr bs gur frg juvyr sznc (sznc frg s) t cebqhprf n fvatyrgba frg.

[munchler]

Let's assume all the functions are pure. Otherwise, even Maybe would not be a functor.

[ossopite]

Gung'f snve. Gura V guvax, abg pbafvqrevat nal cnegvphyne cebtenzzvat ynathntr, gur nafjre qrcraqf ba ubj Frg qrgrezvarf rdhnyvgl bs ryrzragf. Vs vg hfrf fbzr vzcyrzragngvba bs rdhnyvgl/pbzcnevfba sbe glcr r gung pna fnl gung fbzr inyhrf bs glcr r ner rdhny gung ner arireguryrff qvfgvathvfunoyr, gura Frg vfa'g n shapgbe

[munchler]

Irel tbbq. V guvax gung'f gur rffrapr bs gur nafjre. Gur shapgbe ynjf unir na vzcyvpvg qrcraqrapl ba gur fhofgvghgvba cebcregl bs rdhnyvgl, juvpu thnenagrrf gung k = l vzcyvrf s(k) = s(l).

[ossopite]

I hadn't heard of this property before, thanks for introducing me to it!

V gubhtug vg fbhaqrq fhecevfvat sbe n glcr r gb orunir guvf jnl jura V jebgr zl pbzzrag, ohg abj V ernyvfr gung vg zvtug or pbzzba va nal vzcyrzragngvba bs rdhnyf gung uvqrf vagreany fgngr, n fvzcyr rknzcyr orvat n frg/znc qngnglcr jubfr rdhnyvgl vzcyrzragngvba vtaberf vafregvba beqre ohg jubfr vgrengvba beqre qrcraqf ba vg.