I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "Even though some proofs of complexity-theoretic theorems regularly assume some concrete choice of input encoding, one tries to keep the discussion abstract enough to be independent of the choice of encoding. This can be achieved by ensuring that different representations can be transformed into each other efficiently."? 

Mathematical arguments for a statement that essentially gurantee that said statement gurantees a given conclusion are called?