Ambiguity between aorist infinitive and imperative

M., unit 19 Exercise 1, page 161

Translate each form precisely.
11. γύμνασαι

The key gives only one answer: “Exercise yourself” - i.e., weak aorist m/p second person singular imperative.
OK.
What about “to train (others)”, i.e., weak aorist active infinitive?

As far as I can understand, the ending “αι” can be added to the stem (sans the augment) to mean either the aorist infinitive (Unit,19.5.b, p.157) or the aorist 2nd person singular imperative (Unit 19.6, p.158) answer. So, how do I know which meaning applies, out of context as in the exercise? Surely I’m missing something…

Thanks to all.

M. p. 158

"For the weak aorist, the active infinitive and the second person singular middle imperative are identical in verbs with a one-syllable stem: πέμψαι can be the aorist active infinitive, to send, or the second person singular middle imperative, escort (a possible meaning of the middle of πέμπω). "

I guess that as M. says at the top of p.158 “The uses of the aorist infinitive will be presented in Unit 20.” he wants you to concentrate on the finite forms in this chapter.

Thanks for your usual prompt reply.
It completely solves my problem.

I should also have said well done for spotting this. It is always helpful for you to learn where the endings can be the same in different parts of the verb. Another example is in the active imperfect first person singular and third person plural . In context none of these ambiguities should cause any problems.

Hi, the sentence in Mastronarde that immediately follows the one posted by Seneca2008 (pages 158–9) gives you the clue to follow (focusing on the accent and not just the ending):

“When the verb has two or more syllables (including any prefix), then the finite imperative form will have its accent on A, while the nonfinite infinitive has its accent fixed on P: φύλαξαι is the second person singular middle imperative, be on your guard, whereas φυλάξαι is the aorist active infinitive, to guard.”

Hope that helps with the original query! Cheers, Chad

I deliberately left that out because the verb in question was a one syllable stem, but of course, had it not been, the accent would have provided the clue.

Are you sure?

So thinking about this again.

γυμνάσαι Is a third person aorist active optative and aorist active infinitive. [Not Middle as I originally said - See below]

γύμνασαι Is second person singular middle imperative.

Chad was right and I got it wrong. Thanks Joel for making me think again. I can’t count and I am rubbish at accentuation.

No ambiguity but a mystery where my brain was.

I hope there are no further errors!

γυμνάσαι Is . . . aorist middle infinitive.

γυμνάσαι would be the aorist active infinitive. Middle would be γυμνάσασθαι, wouldn’t it? The accent on the first/sigmatic aorist middle infinitive is recessive (unlike its active counterpart), if I’m not mistaken. I can never remember all those tricky accent rules. I never make misteaks, though.

It is γυμνάσασθαι, but I think that thinking of it as recessive probably makes the rules more complicated. In -εσθαι you have γενέσθαι and πιθέσθαι, and for μι verbs, you have -δόσθαι, -θέσθαι, στάσθαι. But -μεναι infinitives act like -σασθαι and -σεσθαι infinitives.

So I think it’s probably better to take all infinitives together, and note that the accent’s place on the root is mostly conserved for infinitives, the real exceptions being the perfect active infinitive in ναι (λελυκέναι), present active infinitive in νυμι (δεικνύναι), the aorist passive (λυθῆναι, but is that just contraction?), and the second aorist active (εῖν, but is this contraction?).

Thanks back to school for me. When I was first taught Greek the instructor didn’t have much command of accents and she skated over them and I have never really caught up. Back to my interrupted project of working through Probert.

I will edit my post thanks as always for the correction.