Mathematical symbols dictionary

–  identically equal,

  –  approximately equal,

~  –  approximately,

0.(12345)  –  the repeating decimal with the period 12345,

N  – the set of natural numbers,

Z –  the set of whole numbers (integers),

R  –  the set of real numbers,

  –  an empty set,

  –  an infinity sign,

  –  an element  x  belongs to a set  X,

 –  an element  x  doesn't belong to a set  X,

X Y –  a set  X  is a subset of a set  Y,

  –  a union of sets  X and Y,

  –  an intersection of sets X and Y,

X \ Y –  a symmetric difference of sets X and Y,

{ u_n } –  a sequence with a general term  u_n ,

[ a, b ]  –  a numerical segment,

  –  numerical semi-segments (semi-intervals),

( a, b )  –  a numerical interval,

  –  a scalar product of vectors ,

  –  a vector product of vectors ,

==>   –  it follows,

<=>   –  equivalent,

  –  perpendicular,

   –  parallel,

  –  a triangle ABC,

–  a function and its derivative.