Circumflex to Distinguish Variable Names
From Why start at x, y, z
Some authors create new variable names by adorning well-known symbols (like \( A \)) with the upright (\( \hat{A} \)), read “A hat”, and inverted (\( \check{A} \)) circumflex, read as “A check”. Depending on the font, these tiny diacritical marks can be hard to discern at a glance. A particularly egregious example is found in Hinze 2012, "Generic Programming with Adjunctions" (p. 5).
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Hinze 2012, "Generic Programming with Adjunctions" (p. 5) creates two new variable names by adorning the letter A with upright and inverted circumflex symbols.