The Statutes of the IMU define these terms as follows:
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3. A country adheres to the Union through an Adhering Organization, which may be its principal academy, a mathematical society, its research council or some other institution or association of institutions, or an appropriate agency of its goverment. The adhering countries are designated hereinafter as the members of the Union. ...
5. In each case, the Adhering Organization shall form a Committee for Mathematics and its adherence to the Union shall not become effective until the composition of the Committee has been reported to and recognized by the members of the Union. The Committee shall act as adviser to the Adhering Organization in matters concerning the Union. The Adhering Organization may, if it wishes, delegate some of its power to the Committee for Mathematics. The Committee for Mathematics shall communicate to the Secretary of the Union the name of its Chairman or Secretary.
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