data/mathematical/82.mml
<math xmlns='http://www.w3.org/1998/Math/MathML' display='inline'><semantics><mrow><msub><mi>h</mi> <mi>i</mi></msub><mo>:</mo><mi>X</mi><mo>→</mo><mo stretchy="false">{</mo><mo lspace="verythinmathspace" rspace="0em">−</mo><mn>1</mn><mo>,</mo><mo>+</mo><mn>1</mn><mo stretchy="false">}</mo></mrow><annotation encoding='application/x-tex'>h_i : X \to \{-1,+1\}</annotation></semantics></math>