Prove or disprove:
- For every \(d \in \mathbb {Z}\) there is a degree \(d\) map \(f_d : T^2 \to S^2\).
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For every \(d \in \mathbb {Z}\) there is a degree \(d\) map \(g_d : S^2 \to T^2\).
Here \(S^2\) is the 2-sphere and \(T^2 = S^1 \times S^1\) is the 2-dimensional torus.