Draw the following condition/event system: N = (C, E, F), given

Specifiy the precondition of e3 as well as the postcondition of e1. Is N simple or/and pure? Given it is not, which edge(s) need(s) to be removed in order to turn N into a pure net? Substantiate or prove your answers concisely.

Conditions: C = {C1, C2, C3, C4}, Events: E={e1, e2, ez}, Relation: F = {(c 1, e 1), (c 1, e 2), (e 1, C2), (e 1, c 3), (e 2, c 2), (e 2, c 3), (e 2, c 4), (2, 3), (c 3, e 3), (c 4, e 3), (e 3, C 1), (e 3, C4)}