title: Matrix operations Prolog
body: <p>Hi I need a help with some prolog functions, please:</p>
  
  <p>Define predicates:</p>
  
  <p>row(X,N,C): C is the row N of matrix X.</p>
  
  <p>column(X,N,C): C is the column N of matrix X.</p>
  
  <p>first_column(X,C,R): the matrix X is formed by first column C and the rest of matrix R.</p>
  
  <p>symmetrical(X): X is a quadratic matrix symmetrical to the diagonal.</p>
  
  <p>The matrix is a list of lists: [[a,b,c],[d,e,f],[g,h,i]]  >>>  </p>
  
  <pre><code>          a b c
            d e f
            g h i
  </code></pre>