Context: Quantity is a property that can exist as a magnitude or multitude. Quantities can be compared in terms of "more", "less", or "equal", or by assigning a numerical value in terms of a unit of measurement. Quantity is among the basic classes of things along with quality, substance, change, and relation. Some quantities are such by their inner nature (as number), while others are functioning as states (properties, dimensions, attributes) of things such as heavy and light, long and short, broad and narrow, small and great, or much and little. A small quantity is sometimes referred to as a quantulum., A definition is a statement of the meaning of a term (a word, phrase, or other set of symbols). Definitions can be classified into two large categories, intensional definitions (which try to give the essence of a term) and extensional definitions (which proceed by listing the objects that a term describes). Another important category of definitions is the class of ostensive definitions, which convey the meaning of a term by pointing out examples. A term may have many different senses and multiple meanings, and thus require multiple definitions., In mathematics , a subsequence is a sequence that can be derived from another sequence by deleting some elements without changing the order of the remaining elements . For example , the sequence \ langle A , B , D \ rangle is a subsequence of \ langle A , B , C , D , E , F \ rangle obtained after removal of elements C , E , and F. The relation of one sequence being the subsequence of another is a preorder . The subsequence should not be confused with substring \ langle A , B , C , D \ rangle which can be derived from the above string \ langle A , B , C , D , E , F \ rangle by deleting substring \ langle E , F \ rangle . The substring is a refinement of the subsequence ., In mathematics, especially in order theory, a preorder or quasiorder is a binary relation that is reflexive and transitive. Preorders are more general than equivalence relations and (non-strict) partial orders, both of which are special cases of a preorder., Mathematics (from Greek  "máthma", knowledge, study, learning) is the study of topics such as quantity (numbers), structure, space, and change. There is a range of views among mathematicians and philosophers as to the exact scope and definition of mathematics., In mathematics, an equivalence relation is a binary relation that is at the same time a reflexive relation, a symmetric relation and a transitive relation. As a consequence of these properties an equivalence relation provides a partition of a set into equivalence classes., In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed. Like a set, it contains members (also called "elements", or "terms"). The number of elements (possibly infinite) is called the "length" of the sequence. Unlike a set, order matters, and exactly the same elements can appear multiple times at different positions in the sequence. Formally, a sequence can be defined as a function whose domain is either the set of the natural numbers (for infinite sequences) or the set of the first "n" natural numbers (for a sequence of finite length "n"). The position of an element in a sequence is its "rank" or "index"; it is the integer from which the element is the image. It depends on the context or of a specific convention, if the first element has index 0 or 1. When a symbol has been chosen for denoting a sequence, the "n"th element of the sequence is denoted by this symbol with "n" as subscript; for example, the "n"th element of the Fibonacci sequence is generally denoted "F"., In mathematics, the natural numbers are those used for counting (as in "there are "six" coins on the table") and ordering (as in "this is the "third" largest city in the country"). In common language, words used for counting are "cardinal numbers" and words used for ordering are "ordinal numbers"., Order theory is a branch of mathematics which investigates the intuitive notion of order using binary relations. It provides a formal framework for describing statements such as "this is less than that" or "this precedes that". This article introduces the field and provides basic definitions. A list of order-theoretic terms can be found in the order theory glossary., Space is the boundless three-dimensional extent in which objects and events have relative position and direction. Physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum known as spacetime. The concept of space is considered to be of fundamental importance to an understanding of the physical universe. However, disagreement continues between philosophers over whether it is itself an entity, a relationship between entities, or part of a conceptual framework., In mathematics, a binary relation on a set "A" is a collection of ordered pairs of elements of "A". In other words, it is a subset of the Cartesian product "A" = . More generally, a binary relation between two sets "A" and "B" is a subset of . The terms correspondence, dyadic relation and 2-place relation are synonyms for binary relation., Subject: subsequence, Relation: instance_of, Options: (A) binary relation (B) branch (C) category (D) city (E) class (F) collection (G) country (H) definition (I) equivalence relation (J) four (K) framework (L) glossary (M) integer (N) language (O) list (P) magnitude (Q) mathematics (R) may (S) order (T) part (U) phrase (V) product (W) quantity (X) rank (Y) sequence (Z) set ([) six (\) space (]) statement (^) study (_) subset (`) table (a) term (b) theory (c) three (d) two (e) value (f) word
Output: binary relation