Commensurate

Two concepts or things are commensurable if they are measurable or comparable by a common standard. Commensurability most commonly refers to

commensurability (mathematics) In mathematics, two non-zero real numbers ''a'' and ''b'' are said to be ''commensurable'' if their ratio ' is a rational number; otherwise ''a'' and ''b'' are called ''incommensurable''. (Recall that a rational number is one that is equivalent ...

. It may also refer to: *

Commensurability (astronomy) Commensurability is the property of two orbiting objects, such as planets, satellites, or asteroids, whose orbital periods are in a rational proportion. Examples include the 2:3 commensurability between the orbital periods of Neptune and Pluto, t ...

, whether two orbital periods are mathematically commensurate. * Commensurability (crystal structure), whether periodic material properties repeat over a distance that is mathematically commensurate with the length of the unit cell. *

Commensurability (economics) Commensurability in economics arises whenever there is a common measure through which the value of two entities can be compared. Commensurability has two versions: * Strong commensurability arises when it is possible to give cardinal Cardinal or ...

, whether economic value can always be measured by money *

Commensurability (ethics) In ethics, two values (or norms, reasons, or goods) are incommensurable (or incommensurate, or incomparable) when they do not share a common standard of measurement or cannot be compared to each other in a certain way. There is a cluster of rela ...

, the commensurability of values in ethics *

Commensurability (group theory) In mathematics, specifically in group theory, two groups are commensurable if they differ only by a finite amount, in a precise sense. The commensurator of a subgroup is another subgroup, related to the normalizer. Commensurability in group theo ...

, when two groups have a subgroup of finite index in common *

Commensurability (philosophy of science) Commensurability is a concept in the philosophy of science whereby scientific theories are said to be "commensurable" if scientists can discuss the theories using a shared nomenclature that allows direct comparison of them to determine which one i ...

* Unit commensurability, a concept in

dimensional analysis In engineering and science, dimensional analysis is the analysis of the relationships between different physical quantities by identifying their base quantities (such as length, mass, time, and electric current) and units of measure (such as ...

that concerns conversion of units of measurement *

Apples and oranges A comparison of apples and oranges occurs when two items or groups of items are compared that cannot be practically compared, typically because of inherent, fundamental and/or qualitative differences between the items. The idiom, ''comparing ...

, common idiom related to incommensurability {{disambiguation it:Incommensurabilità simple:Incommensurability sv:Inkommensurabilitet