Complex sentence: Varoufakis became the finance minister of Greece after the election win of Syriza on 25 January 2015 over the reduction and restructuring of Greece's debt and abolition of austerity measures.
Split into simpler sentences: Varoufakis became the Finance Minister of Greece, after an election win of Syriza on 25 January 2015. Syriza was asking for reduction and restructuring of Greece's debt and abolishment of austerity measures.