fmod EVENPOS is 
	sorts MyItem MyList InVec .
	 
	*** DT definitions (constructors)
	op [] : -> MyList [ctor] .
	op cons : MyItem MyList -> MyList [ctor] .
	 
	*** defined function names (to be induced, preds, bk)
	op evenpos : MyList -> MyList [metadata "induce"] .
	*** input encapsulation
	op in : MyList -> InVec [ctor] .
	 
	vars U V W X Y Z : MyItem .

	eq evenpos([]) = [] .
	eq evenpos(cons(X,[])) = [] .
	eq evenpos(cons(X,cons(Z,[]))) = cons(Z,[]) .
	eq evenpos(cons(X,cons(V,cons(Z,[])))) = cons(V,[]) .
	eq evenpos(cons(X,cons(Z,cons(Y,cons(U,[]))))) = cons(Z,cons(U,[])) .
	eq evenpos(cons(X,cons(W,cons(Z,cons(U,cons(Y,[])))))) = cons(W,cons(U,[])) .
	eq evenpos(cons(X,cons(W,cons(Z,cons(U,cons(Y,cons(V,[]))))))) = cons(W,cons(U,cons(V,[]))) .

endfm