The equivalence of the four hydrogen atoms of methane rested on indirect evidence, e.g.
A special algebra is one which differs from ordinary algebra in the laws of equivalence which its symbols obey.
Equivalent terms, which are not necessarily identical or literal translations, were adopted for the English, French and German languages, the equivalence being closest and most systematic between the English and German terms.
Is not a statement of equality of the same kind as the statement " 153 X 20=3060," but only a statement of equivalence for certain purposes; in other words, it does not convey an absolute truth.
A simple class of cases is that which deals with equivalence of sums of money in different currencies; these cases really come under § 120.