title: Lisp, Remove sublist with two common elements
body: <p>i am programming in Common lisp, and i need an algorithm that delete sublist with (at least) two common elements.</p>
  
  <p>i don't have any idea to how i can solve the problem. I thought to use this: </p>
  
  <p>(defun remove-duplicates-list (list) (remove-duplicates list :test 'equal :key 'cdr)) </p>
  
  <p>but the cdr between the sublists is different, and i just can't figure out how i can count two elements and remove the sublist.
  Also i need to don't remove the "original" sublist (in the example '(1 2 3 4)), bot only (2 3 4) and (1 3 4)</p>
  
  <p>Example : </p>
  
  <p>input: '( (1 2 3 4) (2 3 4) (5 6 7 8) (1 3 4) (9 9 9 9) )</p>
  
  <p>output: '( (1 2 3 4) (5 6 7 8) (9 9 9 9) )</p>
  
  <p>input: '( ((1 . 1) (2 . 2) (3 . 3) (4 . 4)) ((1 . 1) (2 . 2) (4 . 4)))</p>
  
  <p>output : '((1 . 1) (2 . 2) (3 . 3) (4 . 4))</p>
  
  <p>Thank you!</p>
  
  <p>P.s sorry if, at first, i have not explained well my problem, i correct many mistake in the post. this is my first question on this community, so forgive please</p>