title: Converting to XOR conjunctive form
body: <p>The XOR conjunctive form is defined as follows : (a XOR b) and (c XOR d)...etc</p>
  
  <p>and the SAT-XCF is the language defined by the precedent (XOR conjunctive) expressions that are satisfiable.</p>
  
  <p>I would like to know the SAT-XCF is NP hard ? Thus, is there a function able to convert any satisfiable boolean expression into a satisfiable XOR conjunctive form ?</p>
  
  <p>Thank you very much for your contribution.</p>