Assertion: atom's number | /r/HasProperty | impossible to change
Facets:
value: practically
type: MANNER
Source sentences:
text: So the net amount of matter, as measured by the number of quarks (minus the number of antiquarks, which each have a baryon number of −1/3), which is proportional to baryon number, and number of leptons (minus antileptons), which is called the lepton number, is practically impossible to change in any process.