I know that technically, the prepositional (предложный) case is only used for objects of four prepositions: в (in), на (on), при (in presence of / at time of), and по (upon). However, can the prepositions be elided, for example, in dialog?
- О ком вы говорили? - Маше.
To my non-native ear this sounds strange, but I wonder what native speakers would say. Can you provide good, natural-sounding examples where the prepositional case is used without a preposition?