Regulations under the PCT
Rule 10
Terminology and Signs
(a) Units of weights and measures shall be expressed in terms of the metric system, or also expressed in such terms if first expressed in terms of a different system.
(b) Temperatures shall be expressed in degrees Celsius, or also expressed in degrees Celsius, if first expressed in a different manner.
(d) For indications of heat, energy, light, sound, and magnetism, as well as for mathematical formulae and electrical units, the rules of international practice shall be observed; for chemical formulae, the symbols, atomic weights, and molecular formulae, in general use, shall be employed.
(e) In general, only such technical terms, signs and symbols should be used as are generally accepted in the art.
(f) When the international application or its translation is in Chinese, English or Japanese, the beginning of any decimal fraction shall be marked by a period, whereas, when the international application or its translation is in a language other than Chinese, English or Japanese, it shall be marked by a comma.
The terminology and the signs shall be consistent throughout the international application.