bit-flipping decoding

[divon]

My last math course was in 1979, so my understanding of the notation is a bit rusty. Can you explain line 11 in words? Or better, what steps you would take to perform that line?

Thank you very much for your reply, @jefsummers. The steps for performing line 11:

1. Get the value of B based on the matrix H. since matrix H is: , then B_0 which it should take from 1st row of H, the value is: B_0 = [0, 1, 3]. And the same pattern until B_3 that taken from 4th row with value: B_3 = [2, 3, 5]. In my code, it is in line 20.
   
   
2. Set the value for i_prime with the same value of B_j. For example, if j = 0, B_0 = [0, 1, 3], then i_prime = 0, 1, 3. And i_prime will be the constraints for XOR operation of value in matrix M, means that when j = 0, i = 0, B_0 = [0, 1, 3], i_prime = 0, 1, 3, when E_0, 0 for i_prime = 0 the XOR operation will be M_1 ^ M_3 (M_0 is not included since i = i_prime = 0)
   

I have attached the calculation that I have done manually, and I hope it will help.