ἐπί-ἔφ' phonetical changes.

Hallo Leute

I´m here because I have seen in my exercising book this expression: ἐπ’ αὐτοῑς
Ι wonder by one hand on the meaning, -which seems to me an expression like ἐπί τούτοις-. on the other hand, what really makes me confuse is this: why it’s not written ἔφ’ αὐτοῑς ?
what I would like to know is what are the rules to write one and no the other version, Why Holtermann wrote ἐπ’ αὐτοῑς .

Thanks

επι, απο, υπο before a consonant

επ’, απ’. υπ’ before a vowel with a smooth breathing

εφ’, αφ’, υφ’ before a vowel with a rough breathing

Sorry, I gave up on breathing marks because I couldn’t find the right ones.

And do you know how much fun it is to say ἐφ’, ἀφ’, ὐφ’ three times as fast as you can? Try it, it’ll make your day… :smiley:

Thanks for your answers. And yes ἐφ’, ἀφ’, ὐφ’ sound really funny, for me sound like really weird war cry.

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