Number systems
Number systems

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Number systems

Relations

We shall use the symbol (known as tilde or twiddle) to represent a relation between two elements of a set.

Some texts use ρ, rather than , for an arbitrary relation. Certain relations have special symbols; for example,

  • < means is less than,

  • = means is equal to.

Definition

We say that is a relation on a set X if, whenever x, y X, the statement x y is either true or false.

  • If x y is true, then x is related to y.

  • If x y is false, then x is not related to y and we write x y.

The statement x y can be read as ‘x is related to y’ or ‘x twiddles y’.

M208_6

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