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If $mathcal{M}=(M, abla)$ is an affine surface, let $mathcal{Q}(mathcal{M}):=ker(mathcal{H}+frac1{m-1}rho_s)$ be the space of solutions to the quasi-Einstein equation for the crucial eigenvalue. Let $tilde{mathcal{M}}=(M,tilde abla)$ be another affine structure on $M$ which is strongly projectively flat. We show that $mathcal{Q}(mathcal{M})=mathcal{Q}(tilde{mathcal{M}})$ if and only if $ abla=tilde abla$ and that $mathcal{Q}(mathcal{M})$ is linearly equivalent to $mathcal{Q}(tilde{mathcal{M}})$ if and only if $mathcal{M}$ is linearly equivalent to $tilde{mathcal{M}}$. We use these observations to classify the flat Type~$mathcal{A}$ connections up to linear equivalence, to classify the Type~$mathcal{A}$ connections where the Ricci tensor has rank 1 up to linear equivalence, and to study the moduli spaces of Type~$mathcal{A}$ connections where the Ricci tensor is non-degenerate up to affine equivalence.
This paper is devoted to the complete classification of space curves under affine transformations in the view of Cartans theorem. Spivak has introduced the method but has not found the invariants. Furthermore, for the first time, we propound a necess
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