Name | Meaning | MathML
--- | --- | ---
`true` | The boolean value `true` | `<true/>`
`false` | The boolean value `false` | `<false/>`
`pi` | The mathematical constant pi | `<pi/>`
`avogadro` | The numerical value of Avogadro's constant, as defined in the SBML specification | `<csymbol encoding="text" definitionURL="http://www.sbml.org/sbml/symbols/avogadro"> avogadro </csymbol/>`
`time` | Simulation time as defined in SBML | `<csymbol encoding="text" definitionURL="http://www.sbml.org/sbml/symbols/time"> time </csymbol/>`
`inf` or `infinity` | The mathematical constant "infinity" | `<infinity/>`
`nan` or `notanumber` | The mathematical concept "not a number" | `<notanumber/>`
Mathematical symbols defined in the "Level 3" text-string formula syntax.