• Insert all the missing  brackets in the following Scheme function definition:                
  

     define Sumlistweird ls
          cond   null? ls 0
                 =  car ls  0   Sumlistweird  cdr ls
                 else  + 1 
	                 Sumlistweird  cons  -  car ls  1  
		                            cdr ls

• Give a sketchy proof of the Diamond Property for the reduction => (used in the proof of Confluence).
  
  

• Give the definition of well-founded set.