Definition - An
element is a thing contained in a collection.
Definition - T is a
collection of things if and only if T is a collection containing at least a single thing; and, the element or elements in T are of any description except that no collection may contain itself.
The undefined term
collection is used here in the sense that it may contain a single thing or more things. It is not require to contain at least a pair of things, as the term is sometimes used. Also, a collection may not contain itself. It may be an element in another collection, but it cannot be an element contained in itself.
Definition - A
set is either a collection, or a named entity or space that does not contain elements. In the latter case, the set is said to be
empty.
Definition - S is a
collection of things if and only if S is a set; and, if E is an element in S, then E may be of any description.
There is no need to disallow phases such as
a collection of trees or
a set of marbles or
a set of events or
a set of locations. Such phrases can be used to create definitions and identify inferences. Any prohibition against such meanings is a needless attempt to make mathematics unnecessarily abstract.
Definition - A
set K in C is a set such that each element in set K is also an element in a set C.
Definition - C is a
subset of D if and only if C and D are sets and every element in C is also in D.
Definition - C is a
proper subset of D if and only if C and D are sets; and, every element in C is also in D; and, there is at least a single element in D that is not in C.
Definition - The
union of set T and set U is the set S of elements that are each either in set T or set U.
Definition - The
intersection of set T and set U is the set S of elements that are each both in set T or set U; and, set S may be found to be empty.
Definition - An element E is
removed from a named set S if and only if E is in set S, and S is then redefined to exclude E.
Definition - An element E is
inserted in named set S if and only if E is not in set S, and S is then redefined to include E.
Definition - An element E is
copied from set S to set T if and only if E is an element in set S; and, E is inserted in set T.
Definition - An element E is
moved from set S to set T if and only if E is copied from set S to set T, and, E is then removed from set S.
Definition -
One is the name of the amount or quantity that is associated with a single thing; or,
one is the number associated with a single thing.
Definition -
Two is the name of the amount or quantity that is associated with a pair things; or,
two is the number associated with a pair of things.
Definition -
Zero is the name of the amount or quantity that is associated with the absence of things; or,
zero is the number associated with the absence of things.
Definition - Set J is a
set of names if and only if every element in J is a name.
Definition - Element q in set J is a
subscript of K if and only if each of the following statements is true:
K is a name and J is a set of names.
K together with element q in J form a name distinct from K and distinct from element q in J; and, this name is pronounce
K sub q.
The name formed by q and K is written
Kq.
K may be said to be
subscripted; and, K may be said to be
subscripted by q.
Kq may be said to be a name
formed by subscripting.
If Kq isa name formed by subscripting, the q is a
subscript.
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Any name formed by subscripting may be the name of an amount or quantity and therefore a number.
If R is a name and {t, a, h} is a set of names then {Rt, Ra, Rh} is a set of names formed by subscripting.
Definition - A
numeral is a name that is a mark or an ordered set of marks not formed by subscripting.
A numeral could be used as a name for anything. It need not be the name of a number. Here are examples of numerals:
The numeral 0 is a name for the number zero.
The numeral 1 is a name for the number one.
The numeral 2 is a name for the number two.
The numeral 00 is a name for the number zero.
The numeral 01 is a name for the number 1.
The numeral 10 is a name for the number 2.
The numeral 2 is the subscript of name G2.
A subscript is part of a name. The subscripted name may be the name of a number. The number being named in not the being named by the subscipt alone. A numeral may be used as a subscript.
Some things may have more than one name. The numeral 10 may be associated with the number two and may serve as a name for the number two. Likewise, the numeral 2 may be associated with the number two and may serve as a name for the number two.
Definition - Event v is
next in O if and only if O is a set of named events in time; and, g and v are elements in O; and, g occurs, or is to occur, before v occurs; and, v occurs, or is to occur, after g occurs; and, the is no event in O that occurs, or is to occur, both after g and before v.
The definition of next in O applies only to events and not to elements of other kinds. There are many kinds of events, and the definition applies to all events. For instance, an action if an event.
Definition - P is a
procedure if and only if P is a sequence in time beginning with an initial condition J described by a statement K that is named and distinguished with a label; and, a set A of actions is each described by a statement in set S of statements such that each statement in S describes an action that is named and distinguished with a label; and, each statement in S identifies the statement in S that describes the action in A that is to be performed next in A; and, some statement in S describes an action in A that is to be the last action performed by P.
Cuneiform writing in Mesopotamia was primarily devoted to recording amounts of things being traded. Comparisons needed to be made. There is an ancient procedure for comparing the amounts of individually separate items. Originally, containers were used where the otherwise identical procedure defined below uses sets.
Definition - A
one-to-one correspondence is a procedure specified by the following labeled statements describing actions to be performed:
Initial Condition - A pair of sets, j and k, each contain things, while another pair of sets, p and q, are empty.
Action 00 - Move one thing from set j to set p; and, continue by performing Action 01.
Action 01 - Move one thing from set k to set q; and, continue by performing Action 10.
Action 10 - If either set j or set k is empty, stop performing actions. Otherwise continue by performing Action 00
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When this procedure stops performing actions, it is known that set p and set q contain the same quantity of things.
Jim Adrian