In: Advanced Math
Let p be an odd prime (i.e., any prime other than 2). Form two vector spaces V1, V2 over Fp (prime field of order p) with bases corresponding to the edges and faces of an icosahedron (so that V1 has dimension 30 and V2 has dimension 20). Let T : V1 → V2 be the linear transformation defined as follows: given a vector v ∈ V1, T(v) is the vector in V2 whose component corresponding to a given face is the sum of the components of v corresponding to the edges around that face. Prove that T is surjective. (Hint: one option is to look closely at the five edges emanating from a single vertex.)