Triangle Order $\leq_{\bigtriangleup}$ in Singular Categories
  We prove that the triangle order $\leq_{\bigtriangleup}$ in the singular category $D_{sg}(A)$ defines a partial order on the set of isomorphism classes of objects in $D_{sg}(A)$ for a finite-dimensional $k$-algebra $A$. 
Zhengfang Wang
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