Well, you are just throwing random numbers. The topic is an article saying "Precision studies of antihydrogen atoms, for example, have shown that their charact

Well, you are just throwing random numbers. The topic is an article saying "Precision studies of antihydrogen atoms, for example, have shown that their characteristics are identical to hydrogen atoms to beyond the billionth decimal place." This suggest the "characteristic" is some kind of physical property that can be measured and compared.