δοκεῖ (impers.) vs. δοκῶ μοι

[NateD26]

My question is regarding the case of a dependent participle. In the impersonal construction -- δοκεῖ μοι *ἐμὲ* καλῶς ποιεῖσαι ἑκόντα βοηθοῦντά σοι,
it seems to me that I do well if I willingly come to your aid, -- we have dependent participle and modifiers in the accusative.

In the personal -- δοκῶ μοι κακὰ ἐργάζεσθαί σε μὴ βοηθῶν σοι, I think I do you harm if I don't help you, -- they are in the nominative.

What happens when δοκεῖ μοι is not impersonal. Does it then have nom. part.?
And in any case, why isn't the participle in dative case for μοι?

*edited in.*
* edited again. sorry, there's no εἶναι when there's already an inf. standing for a verb other than εἰμί, γίγνομαι, etc.*

[Imber Ranae]

My question is regarding the case of a dependent participle. In the impersonal construction -- δοκεῖ μοι *εἶναι ἐμὲ* καλῶς ποιεῖσαι ἐκόντα βοηθοῦντά σοι,
it seems to me that I do well if I willingly come to your aid, -- we have dependent participle and modifiers in the accusative.

In the personal -- δοκῶ μοι κακὰ ἐργάζεσθαί σε μὴ βοηθῶν σοι, I think I do you harm if I don't help you, -- they are in the nominative.

What happens when δοκεῖ μοι is not impersonal. Does it then have nom. part.?
And in any case, why isn't the participle in dative case for μοι?

*edited in.*

I'm not certain what semantic difference, if any, there may be between the personal and impersonal uses of δοκέω, but the occurrence of the nominative participle βοηθῶν after the personal construction follows the normal pattern for indirect discourse in Greek (i.e. when the subject of the subordinate verb is notionally the same as the subject of the main verb, it is not reiterated with a subject accusative but left implied, and any modifiers it may have then agree with the nominative subject of the main verb instead.)

[NateD26]

Thanks, Imber Ranae.

[ximo]

In ancient Greek there are several possibilities.
First, in the impersonal construction (dokei moi) the infinitive would have a subject in accusative. According to that, the participles can appear in accusative, in the same case as this subject (sometimes elliptical). But if the subject is the same as the dative depending on the verb (dokei moi), then another possibility is that the participle appears in dative. You can find either one or the other option.
In the personal construction besides these there's the possibility of a participle in nominative in the same case as the subject (of dokw, dokousi or any other form in a person different from 3rd singular). But in the example you give dokw moi, the participle could appear in dative (the case of moi) or even in accusative (the case of the subject of the infinitive that depends on dokw).
I think that sometimes the use of one case or another depends on the perception of the speaker, or even on the order of words.