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  2. Python syntax and semantics - Wikipedia

    en.wikipedia.org/wiki/Python_syntax_and_semantics

    Python sets are very much like mathematical sets, and support operations like set intersection and union. Python also features a frozenset class for immutable sets, see Collection types. Dictionaries (class dict) are mutable mappings tying keys and corresponding values. Python has special syntax to create dictionaries ({key: value})

  3. Index notation - Wikipedia

    en.wikipedia.org/wiki/Index_notation

    A vector treated as an array of numbers by writing as a row vector or column vector (whichever is used depends on convenience or context): = (), = Index notation allows indication of the elements of the array by simply writing a i, where the index i is known to run from 1 to n, because of n-dimensions. [1]

  4. Index set - Wikipedia

    en.wikipedia.org/wiki/Index_set

    [1] [2] For instance, if the elements of a set A may be indexed or labeled by means of the elements of a set J, then J is an index set. The indexing consists of a surjective function from J onto A , and the indexed collection is typically called an indexed family , often written as { A j } j ∈ J .

  5. List comprehension - Wikipedia

    en.wikipedia.org/wiki/List_comprehension

    Here, the list [0..] represents , x^2>3 represents the predicate, and 2*x represents the output expression.. List comprehensions give results in a defined order (unlike the members of sets); and list comprehensions may generate the members of a list in order, rather than produce the entirety of the list thus allowing, for example, the previous Haskell definition of the members of an infinite list.

  6. nth root - Wikipedia

    en.wikipedia.org/wiki/Nth_root

    In mathematics, an n th root of a number x is a number r which, when raised to the power of n, yields x: = ⏟ =. The positive integer n is called the index or degree, and the number x of which the root is taken is the radicand.

  7. Raising and lowering indices - Wikipedia

    en.wikipedia.org/wiki/Raising_and_lowering_indices

    We first fix definitions: is a finite-dimensional vector space over a field . Typically K = R {\displaystyle K=\mathbb {R} } or C {\displaystyle \mathbb {C} } . ϕ {\displaystyle \phi } is a non-degenerate bilinear form, that is, ϕ : V × V → K {\displaystyle \phi :V\times V\rightarrow K} is a map which is linear in both arguments, making it ...

  8. Glossary of mathematical symbols - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_mathematical...

    A mathematical symbol is a figure or a combination of figures that is used to represent a mathematical object, an action on mathematical objects, a relation between mathematical objects, or for structuring the other symbols that occur in a formula.

  9. Associative array - Wikipedia

    en.wikipedia.org/wiki/Associative_array

    The basic definition of a dictionary does not mandate an order. To guarantee a fixed order of enumeration, ordered versions of the associative array are often used. There are two senses of an ordered dictionary: The order of enumeration is always deterministic for a given set of keys by sorting.