“composition”的概念、定义、翻译、参考文献-科学参考

composition

Chemical Engineering

The parts of which something is made up. The chemical composition of a substance is made up of its elements. The composition of an alloy is made up of elements (p. 74) whereas the composition of an ore is made up of elements and compounds. The composition of a flow stream to or from a process, or a chemical reaction itself is made up of the various components involved. See process variable.

Computer

1. (relative product) A method of combining functions in a serial manner. The composition of two functions
$f : X \to Y and g : Y \to Z$
is the function
$h : X \to Z$
with the property that
$h (x) = g (f (x))$
This is usually written as g ° f. The process of performing composition is an operation between functions of suitable kinds. It is associative, and identity functions fulfil the role of units.
If R denotes the set of real numbers and
$\begin{array}{l} f : R \to R, f (x) = s i n (x) \\ g : R \to R, g (x) = x^{2} + 3 \end{array}$
then f° g is the function h:
$h : R \to R, h (x) = s i n (x^{2} + 3)$
The idea of composition of functions can be extended to functions of several variables.
2. A subdivision of a positive integer n into parts a₁, a₂,… a_k in which the ordering is significant and in which
$n = a_{1} + a_{2} + \dots + a_{k}$
where each a_i is a positive integer. It is thus similar to a partition (see covering) but in a partition the ordering is not significant. In general the number of compositions of n is 2ⁿ⁻¹.
3. A particular form of association between entities found in object-oriented approaches. The association is used to indicate a hierarchy of objects such that objects lower in the hierarchy are part of objects higher in the hierarchy. Thus the hierarchy indicates a component structure.

单词	composition
释义	composition Chemical Engineering The parts of which something is made up. The chemical composition of a substance is made up of its elements. The composition of an alloy is made up of elements (p. 74) whereas the composition of an ore is made up of elements and compounds. The composition of a flow stream to or from a process, or a chemical reaction itself is made up of the various components involved. See process variable. Computer 1. (relative product) A method of combining functions in a serial manner. The composition of two functions $f : X \to Y and g : Y \to Z$ is the function $h : X \to Z$ with the property that $h (x) = g (f (x))$ This is usually written as g ° f. The process of performing composition is an operation between functions of suitable kinds. It is associative, and identity functions fulfil the role of units. If R denotes the set of real numbers and $\begin{array}{l} f : R \to R, f (x) = s i n (x) \\ g : R \to R, g (x) = x^{2} + 3 \end{array}$ then f° g is the function h: $h : R \to R, h (x) = s i n (x^{2} + 3)$ The idea of composition of functions can be extended to functions of several variables. 2. A subdivision of a positive integer n into parts a₁, a₂,… a_k in which the ordering is significant and in which $n = a_{1} + a_{2} + \dots + a_{k}$ where each a_i is a positive integer. It is thus similar to a partition (see covering) but in a partition the ordering is not significant. In general the number of compositions of n is 2ⁿ⁻¹. 3. A particular form of association between entities found in object-oriented approaches. The association is used to indicate a hierarchy of objects such that objects lower in the hierarchy are part of objects higher in the hierarchy. Thus the hierarchy indicates a component structure.
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