Test stretchy/nonstretchy chars
<math xmlns="http://www.w3.org/1998/Math/MathML"> <mo>|</mo> <mi>H</mi> <mo>|</mo> <mo>+</mo> <mo>⟨</mo> <mi>H</mi> <mo>∣</mo> <mi>H</mi> <mo>⟩</mo> </math>
Author: Design Science, Inc. (D. Doyle, R.Miner)