Question: what is the basic postulates of special theory of relativity

title: Postulates of special relativity
text: ( x 1 − y 1 ) 2 + ( x 2 − y 2 ) 2 + ( x 3 − y 3 ) 2 ( \ displaystyle \ quad ( \ sqrt ( ( x_ ( 1 ) - y_ ( 1 ) ) ^ ( 2 ) + ( x_ ( 2 ) - y_ ( 2 ) ) ^ ( 2 ) + ( x_ ( 3 ) - y_ ( 3 ) ) ^ ( 2 ) ) ) )