When a word v=(v 1 , v 2 v 3 ,..., v 7 ) is received at the decoder’s input port of a (7,3) linear code, the error syndromes s=( s 1 , s 2 , s 3 , s 4 ) for the received word v is calculated as matrix equation ___________ with the known parity-check matrix H 7 ́ 4 of the linear code.