title: How to write a function to check the array for symmetry using lambda calculus?
body: <p>I am studying Lambda Calculus. I need to define a lambda image of a syndicate that returns true or false depending on whether the input array is symmetric from the center or not.
  I will be very happy for any of your help, since this topic is very difficult for me.
  I understand how to define basic constructors such as true or false, as well as addition and multiplication.
  I have some algorithm, as I would like to do:</p>
  
  <ol>
  <li><p>Find the number of elements in the stack.</p></li>
  <li><p>Pull half (with rounding down) of the stack onto another stack.</p></li>
  <li><p>If the number of elements was odd, remove the element from the first stack.</p></li>
  <li>In pairs, remove elements from the stacks and compare, if not equal, return the constructor false, if the stacks are empty, return the constructor true.</li>
  </ol>
  
  <p>UPDATE</p>
  
  <p>1.lenght = λl.l (λx.succ), where succ = λnfx.n f (f x)</p>