LUklbXJvd0c2Iy9JK21vZHVsZW5hbWVHNiJJLFR5cGVzZXR0aW5nR0koX3N5c2xpYkdGJzYkLUkjbWlHRiQ2JVEocmVzdGFydEYnLyUnaXRhbGljR1EldHJ1ZUYnLyUsbWF0aHZhcmlhbnRHUSdpdGFsaWNGJy1JI21vR0YkNi1RIjpGJy9GM1Enbm9ybWFsRicvJSZmZW5jZUdRJmZhbHNlRicvJSpzZXBhcmF0b3JHRj0vJSlzdHJldGNoeUdGPS8lKnN5bW1ldHJpY0dGPS8lKGxhcmdlb3BHRj0vJS5tb3ZhYmxlbGltaXRzR0Y9LyUnYWNjZW50R0Y9LyUnbHNwYWNlR1EsMC4yNzc3Nzc4ZW1GJy8lJ3JzcGFjZUdGTA==

JSFH

Subscript notation is achived in 2 ways: "_" for an index or "Cont Shift _" for textual meaning; id est:

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 and in the later case the under layer of the XML is LUklbXJvd0c2Iy9JK21vZHVsZW5hbWVHNiJJLFR5cGVzZXR0aW5nR0koX3N5c2xpYkdGJzYkLUklbXN1YkdGJDYmLUkjbWlHRiQ2JVEiYUYnLyUnaXRhbGljR1EldHJ1ZUYnLyUsbWF0aHZhcmlhbnRHUSdpdGFsaWNGJy1GIzYlLUYvNiVRImlGJ0YyRjVGMkY1LyUvc3Vic2NyaXB0c2hpZnRHUSIwRicvSSttc2VtYW50aWNzR0YkUSdhdG9taWNGJy9GNlEnbm9ybWFsRic= `#msub(mi("a"),mi("i"))`

Let a function f

QyQ+STcjbXN1YihtaSgiZiIpLG1uKCIxIikpRzYiKiQsKComSSJhR0YlIiIiJkkieEdGJTYjRipGKkYqKiZJImJHRiVGKiZGLDYjIiIjRipGKiomSSJjR0YlRiomRiw2IyIiJEYqRipGMiEiIg==

PkkmZXhwcjFHNiItSShjb2xsZWN0RzYkJSpwcm90ZWN0ZWRHSShfc3lzbGliR0YkNiRJNyNtc3ViKG1pKCJmIiksbW4oIjEiKSlHRiRJImFHRiQ=

LUkjbWlHNiMvSSttb2R1bGVuYW1lRzYiSSxUeXBlc2V0dGluZ0dJKF9zeXNsaWJHRic2JVE1b3V0cHV0fnJlZGlyZWN0ZWQuLi5GJy8lJ2l0YWxpY0dRJXRydWVGJy8lLG1hdGh2YXJpYW50R1EnaXRhbGljRic=

print(); # input placeholder

LCgqJiZJInhHNiI2IyIiIiIiI0kiYUdGJkYpRigqKCwmKiZJImJHRiZGKCZGJTYjRilGKEYoKiZJImNHRiZGKCZGJTYjIiIkRihGKEYoRiRGKEYqRihGKSokRixGKUYo

PkkmZXhwcjJHNiItSShjb2xsZWN0RzYkJSpwcm90ZWN0ZWRHSShfc3lzbGliR0YkNiQtSSVkaWZmR0YoNiRJNyNtc3ViKG1pKCJmIiksbW4oIjEiKSlHRiQmSSJ4R0YkNiMiIiJJImFHRiQ=

LUkjbWlHNiMvSSttb2R1bGVuYW1lRzYiSSxUeXBlc2V0dGluZ0dJKF9zeXNsaWJHRic2JVE1b3V0cHV0fnJlZGlyZWN0ZWQuLi5GJy8lJ2l0YWxpY0dRJXRydWVGJy8lLG1hdGh2YXJpYW50R1EnaXRhbGljRic=

print(); # input placeholder

LCYqJiwmKiZJImJHNiIiIiImSSJ4R0YnNiMiIiNGKEYsKiZJImNHRidGKCZGKjYjIiIkRihGLEYoSSJhR0YnRihGKComJkYqNiNGKEYoRjJGLEYs

LUklc29ydEclKnByb3RlY3RlZEc2JUkmZXhwcjJHNiJJImFHRidJKmFzY2VuZGluZ0dGJw==

LUkjbWlHNiMvSSttb2R1bGVuYW1lRzYiSSxUeXBlc2V0dGluZ0dJKF9zeXNsaWJHRic2JVE1b3V0cHV0fnJlZGlyZWN0ZWQuLi5GJy8lJ2l0YWxpY0dRJXRydWVGJy8lLG1hdGh2YXJpYW50R1EnaXRhbGljRic=

print(); # input placeholder

LCYqJiwmKiZJImJHNiIiIiImSSJ4R0YnNiMiIiNGKEYsKiZJImNHRidGKCZGKjYjIiIkRihGLEYoSSJhR0YnRihGKComJkYqNiNGKEYoRjJGLEYs

KiYtSSNvcEclKnByb3RlY3RlZEc2JCIiI0kmZXhwcjFHNiIiIiJJImFHRikhIiI=

LUkjbWlHNiMvSSttb2R1bGVuYW1lRzYiSSxUeXBlc2V0dGluZ0dJKF9zeXNsaWJHRic2JVE1b3V0cHV0fnJlZGlyZWN0ZWQuLi5GJy8lJ2l0YWxpY0dRJXRydWVGJy8lLG1hdGh2YXJpYW50R1EnaXRhbGljRic=

print(); # input placeholder

LCQqJiwmKiZJImJHNiIiIiImSSJ4R0YnNiMiIiNGKEYoKiZJImNHRidGKCZGKjYjIiIkRihGKEYoJkYqNiNGKEYoRiw=

JSFH