Herbert Weir Smyth, A Greek Grammar for Colleges

OMISSION OF ὤν

[*] 2117. After ἅτε, οἷα, ὡς, or καίπερ, ὤν is often omitted in prose with predicate adjectives: συνδείπνους ἔλαβεν ἀμφοτέρους πρὸς ἑαυτὸν ὡς φίλους ἤδη (ὄντας) he took both to supper with him since they were now friends X. C. 3.2.25. Such omission is rare in prose except after these particles: εἰ ἥττους (ὄντες) ““τῶν πολεμίων ληφθησόμεθα” if we shall be caught at the mercy of our enemies” X. A. 5.6.13. With predicate substantives, even after these particles, ὤν is very rarely omitted (P. R. 568b).

a. In the genitive and accusative absolute the particles of 2117 usually precede when ὤν is omitted. With the genitive absolute the omission is very rare in prose: ὡς ἑτοίμων (ὄντων) χρημάτων just as though the property was at their disposal X. A. 7.8.11; but ἡμέρα_ς ἤδη (οὔσης) it being already day T. 5.59. In poetry the substantive usually suggests the verb: ὑφηγητῆρος οὐδενὸς (ὄντος) φίλων with no friend to guide him S. O. C. 1588. Accusative absolute: ὡς καλὸν (ὂν) ἀγορεύεσθαι αὐτόν on the ground that it is admirable for it (the speech) to be delivered T. 2.35. Without the particles of 2117, the omission of ὄν is poetical (S. Ant. 44). The omission of ὄν with adjectives ending in -ον aids euphony.

b. ἑκών willing, ἄ_κων unwilling are treated like participles (2071): ““ἐμοῦ μὲν οὐχ ἑκόντος” against my will” S. Aj. 455.

c. ὤν must be used when it has the force of in the capacity of.

[*] 2118. A predicate substantive or adjective, coördinated with a participle in the same construction, may omit ὤν; as ““οὐ ῥᾴδιον ἦν μὴ ἁθρόοις καὶ ἀλλήλους περιμείνα_σι διελθεῖν τὴν πολεμία_ν” it was not easy for them to pass through the enemy's country except in a body and after having waited for one another” T. 5.64.

[*] 2119. ὤν may be omitted with verbs taking a supplementary participle; so with verbs meaning to perceive (2111 ff.), know, show, announce, find, discover, etc.; especially with φαίνομαι, τυγχάνω (poet. κυρῶ), διατελῶ, διαγίγνομαι, rarely with περιορῶ and συμβαίνω. Thus, ὁρῶ μέγαν (ὄντα) ““τὸν ἀγῶνα” I see that the contest is important” T. 2.45, ἂ_ν ἐν Χερρονήσῳ πύθησθε Φίλιππον (ὄντα) if you learn that Philip is in Chersonesus D. 4.41, εὶ ψευδὴς φαίνοιτο (ὤν) ““ὁ Λωβρύα_ς” if Gobryas seem to be false” X. C. 5.2.4, εἴ τις εὔνους (ὤν) ““τυγχάνει” if any one happens to be friendly” Ar. Eccl. 1141, ἀχίτων (ὤν) ““διατελεῖς” you are continually without a tunic” X. M. 1.6.2.