The reaction between Cu3PO4 and KMnO4 can be predicted as follows:

Cu3PO4 (copper(II) phosphate) + KMnO4 (potassium permanganate) -> Cu(NO3)2 (copper(II) nitrate) + K2MnO4 (potassium manganate) + MnO2 (manganese dioxide) + H3PO4 (phosphoric acid)

In this reaction, Cu3PO4 is oxidized by KMnO4, which is reduced. The products of the reaction are Cu(NO3)2, K2MnO4, MnO2, and H3PO4.