diff --git a/kenzo.asd b/kenzo.asd
index 3237f25..f185647 100644
--- a/kenzo.asd
+++ b/kenzo.asd
@@ -57,7 +57,9 @@
              (:file "cl-space-efhm")
              (:file "whitehead")
              (:file "smith")
-             (:file "sage-interface")             
+             (:file "sage-interface")
+             (:file "finite-topological-spaces-aux")     
+             (:file "finite-topological-spaces-class")          
              (:module "anromero"
              :components
 	     ((:file "resolutions")
diff --git a/src/finite-topological-spaces-aux.lisp b/src/finite-topological-spaces-aux.lisp
new file mode 100644
index 0000000..a683f4e
--- /dev/null
+++ b/src/finite-topological-spaces-aux.lisp
@@ -0,0 +1,241 @@
+;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Base: 10 -*
+
+;;  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES 
+;;  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES 
+;;  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES 
+
+(IN-PACKAGE #:cat)
+
+(PROVIDE "finite-topological-spaces-aux")
+
+;;
+;;   Auxiliary functions (most of them in 'NewSmith')
+;;
+
+
+(DEFUN MAJTERME (pl pc val)
+  #| Same 'maj-terme' but changing '=' by 'eq' |#
+  (if (eq val 0)
+      (if (eq (left pl) (up pc)) (supprimer-terme pl pc))
+    (if (eq (left pl) (up pc))
+          (setf (val (left pl)) val)
+      (inserer-terme pl pc val))))
+
+
+(DEFUN EQUALMATRIX (mtrx1 mtrx2)
+  #| Same 'equal-matrix' but changing 'line-number' by 'nlig' and 'column-number' by 'ncol' |#
+  (declare (type matrice mtrx1 mtrx2))
+  (the boolean
+    (let ((line-number (nlig mtrx1)))
+      (declare (type fixnum line-number))
+      (unless (eql line-number (nlig mtrx2))
+        (return-from equalmatrix +false+))
+      (unless (eql (ncol mtrx1) (ncol mtrx2))
+        (return-from equalmatrix +false+))
+      (do ((il 1 (1+ il)))
+          ((> il line-number))
+        (declare (type fixnum il))
+        (let ((p10 (baselig mtrx1 il))
+              (p20 (baselig mtrx2 il)))
+          (declare (type t-mat p10 p20))
+          (do ((p1 (left p10) (left p1))
+               (p2 (left p20) (left p2)))
+              (nil)
+            (declare (type t-mat p1 p2))
+            (when (eq p1 p10)
+              (unless (eq p2 p20)
+                (return-from equalmatrix +false+))
+              (return))
+            (when (eq p2 p20)
+              (unless (eq p1 p10)
+                (return-from equalmatrix +false+)))
+            (unless (eql (icol p1) (icol p2))
+              (return-from equalmatrix +false+))
+            (unless (eql (val p1) (val p2))
+              (return-from equalmatrix +false+)))))
+      (return-from equalmatrix +true+))))
+
+
+(DEFUN MTRX-PRDC (mtrx1 mtrx2)
+  #| Same 'mtrx-prdc' but changing 'line-number' by 'nlig' and 'column-number' by 'ncol' |#
+  (declare (type matrice mtrx1 mtrx2))
+  (the matrice
+    (let ((nl (nlig mtrx1))
+          (nc (ncol mtrx2))
+          (n (ncol mtrx1)))
+      (declare (type fixnum nl nc n))
+      (assert (eql n (nlig mtrx2)))
+      (let ((rslt (creer-matrice nl nc)))
+        (declare (type matrice rslt))
+        (do ((il 1 (1+ il)))
+            ((> il nl))
+          (declare (type fixnum il))
+          (do ((pl01 (baselig mtrx1 il))
+               (pl0r (baselig rslt il))               
+               (ic 1 (1+ ic)))
+              ((> ic nc))
+            (declare (type t-mat pl01 pl0r) (type fixnum ic))
+            (let ((pl (left pl01))
+                  (pc (up (basecol mtrx2 ic)))
+                  (sum 0))
+              (declare (type t-mat pl pc) (type fixnum sum))
+              (loop
+                (let ((ilic (icol pl))
+                      (icil (ilig pc)))
+                  (declare (type fixnum ilic icil))
+                  (when (zerop ilic) (return))
+                  (when (zerop icil) (return))
+                  (cond ((eql ilic icil)
+                         (incf sum (safe-* (val pl) (val pc)))
+                         (setf pl (left pl) pc (up pc)))
+                        ((> ilic icil)
+                         (setf pl (left pl)))
+                        (t
+                         (setf pc (up pc))))))
+              (unless (zerop sum)
+                (inserer-terme pl0r (basecol rslt ic) sum)))))
+        rslt))))
+
+
+(DEFUN SAFE-* (arg1 arg2)
+  #| This is in 'NewSmith' |#
+  (declare (type fixnum arg1 arg2))
+  (let ((rslt (* arg1 arg2)))
+    (declare (type integer rslt))
+    (if (typep rslt 'fixnum)
+        rslt
+      (error "Fixnum-overflow in (safe-* ~D ~D)." arg1 arg2))))
+
+
+(DEFUN SAFE-+ (arg1 arg2)
+  #| This is in 'NewSmith' |#
+  (declare (type fixnum arg1 arg2))
+  (let ((rslt (+ arg1 arg2)))
+    (declare (type integer rslt))
+    (if (typep rslt 'fixnum)
+        rslt
+      (error "Fixnum-overflow in (safe-+ ~D ~D)." arg1 arg2))))
+
+
+(DEFUN SAFE-- (arg)
+  #| This is in 'NewSmith' |#
+  (declare (type fixnum arg))
+  (let ((rslt (- arg)))
+    (declare (type integer rslt))
+    (if (typep rslt 'fixnum)
+        rslt
+      (error "Fixnum-overflow in (SAFE-- ~D)." arg))))
+
+
+(DEFUN 0NEW-COLUMN (mtrx icol list)
+  #| This is 'new-column' in 'NewSmith' |#
+  (declare (type matrice mtrx) (type fixnum icol) (type list list))
+  (the matrice
+    (let ((peigne (peigne-hor mtrx (baselig mtrx 0) icol))
+          (pc0 (basecol mtrx icol)))
+      (declare (type list peigne) (type t-mat pc0))
+      (map nil #'(lambda (item)
+                   (declare (type t-mat item))
+                   (when (eq (up pc0) (left item))
+                     (supprimer-terme item pc0)))
+        peigne)
+      (do ((markp (nreverse peigne) (cdr markp))
+           (ilig 1 (1+ ilig))
+           (markc list))
+          ((endp markc))
+        (declare (type list markp markc) (type fixnum ilig))
+        (when (eql (caar markc) ilig)
+          (inserer-terme (car markp) pc0 (cadar markc))
+          (setf markc (cdr markc))))      
+      mtrx)))
+
+
+(DEFUN 0COLUMN-OP (mtrx lambda icol1 icol2)
+  #| This is 'column-op' in 'NewSmith' |#
+  (declare
+   (type matrice mtrx)
+   (type fixnum lambda icol1 icol2))
+  (the matrice
+    (let ((mark1 (extract-column mtrx icol1))
+          (mark2 (extract-column mtrx icol2))
+          (new-column2 +empty-list+))
+      (declare (type list mark1 mark2 new-column2))
+      (loop
+        (when (endp mark1)
+          (setf new-column2 (nreconc new-column2 mark2))
+          (return))
+        (when (endp mark2)
+          (setf new-column2
+            (nreconc new-column2
+                     (mapcar #'(lambda (item)
+                                 (declare (type list item))
+                                 (list (first item)
+                                       (safe-* lambda (second item))))
+                       mark1)))
+          (return))
+        (let ((ilig1 (caar mark1))
+              (ilig2 (caar mark2)))
+          (declare (type fixnum ilig1 ilig2))
+          (cond ((< ilig1 ilig2)
+                 (push (list ilig1 (safe-* lambda (second (pop mark1))))
+                       new-column2))
+                ((> ilig1 ilig2)
+                 (push (list ilig2 (second (pop mark2))) new-column2))
+                (t (let ((new-val (safe-+ (safe-* lambda (second (pop mark1)))
+                                     (second (pop mark2)))))
+                     (declare (type fixnum new-val))
+                     (unless (zerop new-val)
+                       (push (list ilig1 new-val) new-column2)))))))
+      (0new-column mtrx icol2 new-column2)
+      mtrx)))
+
+
+(DEFUN 0COLUMN-SWAP (mtrx icol1 icol2)
+  #| This is 'column-swap' in 'NewSmith' |#
+  (declare
+    (type matrice mtrx) (type fixnum icol1 icol2))
+  (the matrice
+    (let ((new-column1 (extract-column mtrx icol2))
+          (new-column2 (extract-column mtrx icol1)))
+      (declare (type list new-column1 new-column2))
+      (0new-column mtrx icol1 new-column1)
+      (0new-column mtrx icol2 new-column2)
+      mtrx)))
+
+
+(DEFUN 0COLUMN-MINUS (mtrx icol)
+  #| This is 'column-minus' in 'NewSmith' |#
+  (declare (type matrice mtrx) (type fixnum icol))
+  (the matrice
+    (0new-column mtrx icol
+                (mapcar #'(lambda (item)
+                            (declare (type list item))
+                            (the list
+                              (list (first item)
+                                    (safe-- (second item)))))
+                  (extract-column mtrx icol)))))
+
+
+(DEFUN EXTRACT-COLUMN (mtrx icol)
+  #| This is in 'NewSmith' |#
+  (declare (type matrice mtrx) (type fixnum icol))
+  (the list
+    (let ((pc0 (basecol mtrx icol)))
+      (declare (type t-mat pc0))
+      (do ((pc (up pc0) (up pc))
+           (rslt +empty-list+ (cons (list (ilig pc) (val pc)) rslt)))
+          ((eq pc pc0) rslt)
+        (declare (type t-mat pc) (type list rslt))))))
+
+
+(DEFUN EXTRACT-LINE (mtrx ilig)
+  #| This is in 'NewSmith' |#
+  (declare (type matrice mtrx) (type fixnum ilig))
+  (the list
+    (let ((pl0 (baselig mtrx ilig)))
+      (declare (type t-mat pl0))
+      (do ((pl (left pl0) (left pl))
+           (rslt +empty-list+ (cons (list (icol pl) (val pl)) rslt)))
+          ((eq pl pl0) rslt)
+        (declare (type t-mat pl) (type list rslt))))))
+
diff --git a/src/finite-topological-spaces-class.lisp b/src/finite-topological-spaces-class.lisp
new file mode 100644
index 0000000..973c130
--- /dev/null
+++ b/src/finite-topological-spaces-class.lisp
@@ -0,0 +1,450 @@
+;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Base: 10 -*
+
+;;  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES 
+;;  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES 
+;;  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES  FINITE-TOPOLOGICAL-SPACES 
+
+(IN-PACKAGE #:cat)
+
+(PROVIDE "finite-topological-spaces-class")
+
+;;
+;;  Finite topological spaces
+;;
+
+
+(DEFMACRO INSERT-TERM (mat ilig icol val)
+  #| Insert the value 'val' in the ('ilig' 'icol')-entry of 'mat' |#
+  `(majterme (chercher-hor (baselig ,mat ,ilig) ,icol)
+             (chercher-ver (basecol ,mat ,icol) ,ilig)
+             ,val))
+
+
+(DEFUN CONVERTARRAY (array)
+  #| Convert an 'array' to a 'matrice' |#
+  (let* ((numfil (array-dimension array 0))
+         (numcol (array-dimension array 1))
+         (rslt (creer-matrice numfil numcol)))
+    (dotimes (j numcol)
+      (dotimes (i numfil)
+        (insert-term rslt (1+ i) (1+ j) (aref array i j))))
+    rslt))
+
+
+(DEFUN CONVERTMATRICE (matrice)
+  #| Convert a 'matrice' to an 'array' |#
+  (let* ((numfil (nlig matrice))
+         (numcol (ncol matrice))
+         (rslt (make-array (list numfil numcol) :initial-element 0)))
+    (dotimes (i numfil)
+      (dotimes (j numcol)
+        (let ((Mij (terme matrice (1+ i) (1+ j))))
+          (unless (zerop Mij)
+            (setf (aref rslt i j) Mij)))))
+    rslt))
+
+
+(DEFUN VER (matrix)
+  (let ((mat '()))
+    (typecase matrix
+      (matrice (setf mat matrix))
+      (T (setf mat (convertarray matrix))))
+    (format t "~%")
+    (format t "           ========== MATRIX ~A row(s) + ~A column(s) ==========~%~%" (nlig mat) (ncol mat))
+    (do ((i 1 (1+ i))) ((> i (nlig mat)))
+      (format t "           ")
+      (do ((j 1 (1+ j))) ((> j (ncol mat)))
+        (if (< (terme mat i j) 0)
+            (format t " ~A " (terme mat i j))
+          (format t "  ~A " (terme mat i j))))
+      (format t "  ~%"))))
+
+
+(DEFUN EXTRACT-COLUMN2 (mtrx icol list)
+  #| Modification of 'EXTRACT-COLUMN' in order to extract only the elements in the column 'icol' whose row indexes are in the list 'list' |#
+  (declare (type matrice mtrx) (type fixnum icol) (type list list))
+  (the list
+       (let ((pc0 (basecol mtrx icol))
+             (lst list))
+         (declare (type t-mat pc0))
+         (do ((pc (up pc0) (up pc))
+              (rslt +empty-list+ (if (find (ilig pc) lst)
+                                     (progn
+                                       (setf lst (remove (ilig pc) lst))
+                                       (cons (list (ilig pc) (val pc)) rslt))
+                                   rslt)))
+             ((eq pc pc0) rslt)
+           (declare (type t-mat pc) (type list rslt))))))
+
+
+(DEFUN SUBMATRIX (mtrx rows cols)
+  #| Extract the submatrix of 'mtrx' formed by the rows whose indexes are in 'rows' and the columns whose indexes are in 'cols' |#
+  (declare (type matrice mtrx)
+           (type list rows cols))
+  (let ((rslt (creer-matrice (length rows) (length cols))))
+    (do ((k 1 (1+ k))
+         (columnas cols (cdr columnas)))
+        ((endp columnas) rslt)
+      (0new-column rslt k (let ((valor NIL))
+                            (do ((j (length rows) (1- j))
+                                 (rslt2 +empty-list+ (if (setf valor (second (find (nth (1- j) rows) (extract-column2 mtrx (car columnas) rows) :key #'first)))
+                                                         (cons (list j valor) rslt2)
+                                                       rslt2)))
+                                ((< j 1) rslt2)))))))
+
+
+(DEFUN NILPOT (matrix)  
+  (declare (type matrice matrix))
+  (let ((rslt (copier-matrice matrix)))
+    (loop for k from 1 to (nlig rslt)
+          do (insert-term rslt k k 0))
+    rslt))
+
+
+(DEFUN NILPOT-1 (matrix)  
+  (declare (type matrice matrix))
+  (let ((rslt (copier-matrice matrix)))
+    (loop for k from 1 to (nlig rslt)
+          do (insert-term rslt k k 1))
+    rslt))
+
+
+(DEFUN ADD-ROWS (matrice pos num)
+  #| Add 'num' rows from position 'pos' |#
+  (let ((rslt (creer-matrice (+ (n-lig matrice) num) (n-col matrice))))
+    (do ((i 1 (1+ i)))
+        ((eq i pos))
+      (do ((ptl1 (baselig matrice i))
+           (pl1 (left (baselig matrice i)) (left pl1))
+           (pl2 (baselig rslt i) (left pl2)))
+          ((eq pl1 ptl1))
+        (inserer-terme pl2 (basecol rslt (icol pl1)) (val pl1))))
+    
+    (do ((i pos (1+ i)))
+        ((> i (n-lig matrice)) rslt)
+      (do ((ptl1 (baselig matrice i))
+           (pl1 (left (baselig matrice i)) (left pl1))
+           (pl2 (baselig rslt (+ i num)) (left pl2)))
+          ((eq pl1 ptl1))
+        (inserer-terme pl2 (basecol rslt (icol pl1)) (val pl1))))))
+
+
+(DEFUN ADD-COLS (matrice pos num)
+  #| Add 'num' columns from position 'pos' |#
+  (let ((rslt (creer-matrice (n-lig matrice) (+ (n-col matrice) num))))
+    (do ((i 1 (1+ i)))
+        ((eq i pos))
+      (do ((ptc1 (basecol matrice i))
+           (pc1 (up (basecol matrice i)) (up pc1))
+           (pc2 (basecol rslt i) (up pc2)))
+          ((eq pc1 ptc1))
+        (inserer-terme (baselig rslt (ilig pc1)) pc2 (val pc1))))
+
+      (do ((i pos (1+ i)))
+          ((> i (n-col matrice)) rslt)
+        (do ((ptc1 (basecol matrice i))
+             (pc1 (up (basecol matrice i)) (up pc1))
+             (pc2 (basecol rslt (+ i num)) (up pc2)))
+            ((eq pc1 ptc1))
+          (inserer-terme (baselig rslt (ilig pc1)) pc2 (val pc1))))))
+
+
+(DEFMACRO ADD-POINTS (matrice pos num)
+  #| Add 'num' points from position 'pos' |#
+  `(add-cols (add-rows ,matrice ,pos ,num) ,pos ,num))
+
+
+(DEFUN STONGMAT (topogenous)
+  #| Stong matrice from the topogenous matrice 'topogenous' |#
+  (declare (type matrice topogenous))
+  (let* ((dim (nlig topogenous))
+         (rslt (identite dim)))
+    (declare (type fixnum dim))
+    (if (or (eq dim 1) (eq dim 2))
+        (return-from stongmat topogenous)
+      
+      (do ((i 1 (1+ i))) ((> i dim) rslt)
+        (do ((j (1+ i) (1+ j))) ((> j dim))
+          (cond ((eq j (1+ i)) (insert-term rslt i j (terme topogenous i j)))
+                ((eq (terme topogenous i j) 0))
+                (T (let ((parada 0))
+                     (do ((k (1+ i) (1+ k))) ((or (> k (1- j)) (eq parada 1)))
+                       (cond ((and (eq (terme topogenous i k) 1) (eq (terme topogenous k j) 1)) (setf parada 1))
+                             ((and (eq k (1- j)) (eq parada 0)) (insert-term rslt i j 1))))))))))))
+
+
+(DEFUN TOPMAT (stong)
+  #| Topogenous matrice from the Stong matrice 'stong' |#
+  (declare (type matrice stong))
+  (let* ((dim (nlig stong))
+         (rslt (identite dim)))
+    (declare (type fixnum dim))
+    (if (or (eq dim 1) (eq dim 2))
+        (return-from topmat stong)
+
+      (do ((k 2 (1+ k))) ((> k dim) rslt)
+        (if (eq k 2)
+            (do ((i 1 (1+ i))) ((> i (1- dim)))
+              (insert-term rslt i (1+ i) (terme stong i (1+ i))))
+          
+          (do ((i 1 (1+ i))) ((> i (1+ (- dim k))))
+            
+            (if (eq (terme stong i (1- (+ i k))) 1)
+                (insert-term rslt i (1- (+ i k)) 1)
+              
+              (if (eq (let ((indicator 0))
+                        (do ((r (1+ i) (1+ r))) ((or (> r (- (+ i k) 2)) (eq indicator 1))) 
+                          (if (and (eq (terme rslt i r) 1) (eq (terme rslt r (1- (+ i k))) 1))
+                              (setf indicator 1))) indicator) 1)
+                  (insert-term rslt i (1- (+ i k)) 1)))))))))
+
+
+(DEFUN RANDOMTOP (dim dens)
+  #| A 'dim' x 'dim' random topogenous matrice |#
+  (declare (fixnum dim))
+  (let ((limite (truncate (/ (* dens (- dim 2) (- dim 1)) 2)))
+        (rslt (identite dim))
+        (contador 1)
+        (base (make-array dim)))
+    (unless (= dim 1)   
+      (do () ((> contador limite))
+        (let* ((j1 (1+ (random (1- dim))))
+               (i1 (random j1)))
+          (if (find i1 (aref base j1))
+              (incf contador) ; Avoiding an infinite loop...
+            (progn
+              (push i1 (aref base j1))
+              (setf (aref base j1) (union (aref base j1) (aref base i1)))
+              (loop for k in (>a-b< j1 dim)
+                    if (find j1 (aref base k))
+                    do (and (pushnew i1 (aref base k))
+                            (setf (aref base k) (union (aref base k) (aref base i1))) ; Improve...
+                            (incf contador)))))))
+      (loop for j in (<a-b< 1 dim)
+            do (mapcar #'(lambda (elem) (insert-term rslt (1+ elem) (1+ j) 1)) (aref base j))))
+    rslt))
+
+
+(DEFMACRO RANDOMSTONG (dim dens)
+  #| A 'dim' x 'dim' random Stong matrice |#
+  `(stongmat (randomtop ,dim ,dens)))
+
+
+(DEFUN ALTUR (stong lst) 
+  (if (null lst)
+      NIL
+    (let ((minimals (loop for n in lst
+                          if (null (loop for i from 0 to (1- (position n lst))
+                                         thereis (eq (terme stong (nth i lst) n) 1)))
+                          collect n)))
+      (cons minimals (altur stong (reverse (set-difference lst minimals)))))))
+
+(DEFMETHOD HEIGHTS ((stong matrice))
+  #| List of elements separated by heights |#
+  (altur stong (<a-b> 1 (ncol stong))))
+
+
+(DEFCLASS FINITE-SPACE ()
+   ;; TOPogenous matrix
+  ((top :type matrice :initarg :top :reader top)
+   ;; STONG matrix
+   (stong :type matrice :initarg :stong :reader stong)
+   ;; HEIGHTS
+   (heights :type list :initarg :heights :reader heights)
+   ;; IDentification NuMber
+   (idnm :type fixnum :initform (incf *idnm-counter*) :reader idnm)
+   ;; ORiGiN
+   (orgn :type list :initarg :orgn :reader orgn)))
+
+
+(DEFMETHOD SLOT-UNBOUND (class (finspace finite-space) (slot-name (eql 'heights)))
+  (declare (ignore class))
+  (the list
+       (setf (slot-value finspace 'heights) (heights (stong finspace)))))
+
+
+(DEFMETHOD SLOT-UNBOUND (class (finspace finite-space) (slot-name (eql 'top)))
+  (declare (ignore class))
+  (the matrice
+       (setf (slot-value finspace 'top) (topmat (stong finspace)))))
+
+
+(DEFMETHOD SLOT-UNBOUND (class (finspace finite-space) (slot-name (eql 'stong)))
+  (declare (ignore class))
+  (the matrice
+       (setf (slot-value finspace 'stong) (stongmat (top finspace)))))
+
+
+(DEFMETHOD SLOT-UNBOUND (class (finspace finite-space) (slot-name (eql 'orgn)))
+  (declare (ignore class))
+  (the list
+       (setf (slot-value finspace 'orgn) `(FINITE-SPACE ,(idnm finspace))))) ;(1+ *idnm-counter*)
+
+
+(DEFMETHOD INITIALIZE-INSTANCE :after ((finspace FINITE-SPACE) &rest rest)
+  (set (intern (format nil "K~D" (idnm finspace))) finspace))
+
+
+(DEFVAR *FINITE-SPACE-LIST*)
+(SETF *FINITE-SPACE-LIST* +empty-list+)
+(PUSHNEW '*FINITE-SPACE-LIST* *list-list*)
+
+
+(DEFMETHOD PRINT-OBJECT ((finspace finite-space) stream)
+ (the finite-space
+   (progn
+      (format stream "[K~D Finite-Space]" (idnm finspace))
+      finspace)))
+
+
+(DEFUN BUILD-FINITE-SPACE (&key top stong heights orgn)
+  (the finite-space
+       (progn
+         (let ((already (find orgn *finite-space-list* :test #'equal :key #'orgn)))
+           (declare (type (or finite-space null) already))
+           (when already
+             (return-from build-finite-space already)))
+         (let ((finspace (make-instance 'finite-space)))
+           (declare (type finite-space finspace))
+           (if top     (setf (slot-value finspace 'top) top))
+           (if stong   (setf (slot-value finspace 'stong) stong))
+           (if heights (setf (slot-value finspace 'heights) heights))
+           (if orgn    (setf (slot-value finspace 'orgn) orgn))
+           (push finspace *finite-space-list*)
+           finspace))))
+
+
+(DEFUN TOPOLOGY (dmns dens)
+  #| Random Finite-Space of size 'dmns' and density 'dens' |#
+  (declare (fixnum dmns))
+  (unless (plusp dmns)
+    (error "In TOPOLOGY, the dimension ~D should be positive." dmns))
+  (build-finite-space :top (randomtop dmns dens)
+                      :orgn `(RANDOM-TOPOLOGY ,(1+ *idnm-counter*))))
+
+
+(DEFUN ADMISSIBLE (topogenous i j)
+  #| 'T' if Hat-Uj-{i} is contractible (the edge (i j) is admissible) |#
+  (if (and (> j i) (eq (terme topogenous i j) 1))
+      (the boolean
+           (eq (length (core_list topogenous
+                                  (loop for k from 1 to (1- j)
+                                        unless (or (zerop (terme topogenous k j)) (eq k i))
+                                        collect k))) 1))))
+
+
+(DEFMETHOD ADMISSIBLE-P ((topogenous matrice)) 
+  
+  (the boolean
+       (let ((fin T)
+             (stong (stongmat topogenous)))
+         (do ((j 2 (1+ j))) ((or (null fin) (> j (ncol topogenous))) fin)
+           (do ((i 1 (1+ i))) ((or (null fin) (> i (1- j))))
+             (if (= (terme stong i j) 1)
+                 (if (null (admissible topogenous i j))
+                     (setf fin NIL))))))))
+
+
+(DEFMETHOD ADMISSIBLE-P ((finspace finite-space))
+
+  (the boolean
+       (let ((fin T))
+         (do ((j 2 (1+ j))) ((or (null fin) (> j (ncol (top finspace)))) fin)
+           (do ((i 1 (1+ i))) ((or (null fin) (> i (1- j))))
+             (if (= (terme (stong finspace) i j) 1)
+                 (if (null (admissible (top finspace) i j))
+                     (setf fin NIL))))))))
+
+
+(DEFMETHOD DVFIELD ((finspace finite-space))
+  #| Discrete vector field on 'finspace' |#
+  (declare (finite-space finspace))
+  (let* ((m_stong (matrice-to-lmtrx (nilpot (stong finspace))))
+         (m_top (matrice-to-lmtrx (nilpot (top finspace))))
+         (rown (length m_stong))
+         (status (make-array rown :initial-element '()))
+         (used nil) 
+         (vf '()))
+    (dotimes (i rown) ; Here it is working on the columns. 'rown' is the dimension of the space
+      (unless (member i used)
+        (let ((coli_stong (svref m_stong i))
+              (coli_top (svref m_top i)))
+          (when coli_stong
+            (let ((rowilist (mapcar #'car coli_stong))
+                  (rowilist_top (mapcar #'car coli_top)))
+              (declare (type list rowilist rowilist_top))
+              (dolist (rowi rowilist)    
+                (declare (type fixnum rowi))
+                (let ((rowistatus (svref status rowi)))
+                  (unless (eql 1 rowistatus)
+                    (unless (member rowi used)
+                      (when (and (admissible (top finspace) (1+ rowi) (1+ i))
+                                 (null-intersection-p rowistatus rowilist))
+                        (setf (svref status rowi) 1)
+                        (setf rowistatus (insert rowi rowistatus))
+                        (push (list (1+ rowi) (1+ i)) vf)
+                        (push i used)    
+                        (push rowi used)    
+                        (dolist (item rowilist_top)
+                          (unless (= item rowi)
+                            (case (svref status item)
+                              (1 (dotimes (rowj rown)
+                                   (let ((rowjstatus (svref status rowj)))
+                                     (unless (eql 1 rowjstatus)
+                                       (when (member item rowjstatus)
+                                         (setf (svref status rowj)
+                                               (union-merge rowistatus rowjstatus)))))))
+                              (otherwise
+                               (setf (svref status item)
+                                     (union-merge (member item rowilist_top) (union-merge rowistatus (svref status item))))))))
+                        (return)))))))))))
+    (return-from DVFIELD (nreverse vf))))
+
+
+(DEFMETHOD DVFIELD ((topogenous matrice))
+  #| Discrete vector field on a matrice 'topogenous' |#
+  (dvfield (make-instance 'finite-space
+                          :top topogenous)))
+
+
+;;
+;;  Special examples of Finite topological spaces
+;;
+
+
+(DEFUN FINITE-MODEL-SPHERE (dmns)
+  #| Minimal finite model of the 'dmns'-dimensional sphere |#
+  (declare (fixnum dmns))
+  (if (minusp dmns)
+      (error "In FINITE-MODEL-SPHERE, the dimension ~D must be non-negative integer." dmns))
+  (build-finite-space
+   :stong (let ((rslt (identite (+ (* 2 dmns) 2))))
+            (unless (= dmns 0)
+              (do ((i 1 (1+ i))) ((> i (* 2 dmns)))
+                (insert-term rslt i (+ i 2) 1)
+                (if (= (mod i 2) 0)
+                    (insert-term rslt i (+ i 1) 1)
+                  (insert-term rslt i (+ i 3) 1))))
+            rslt)
+   :heights (let ((rslt (<a-b> 1 (+ (* 2 dmns) 2))))
+              (dotimes (q (1+ dmns)) 
+                (setf rslt (append (cddr rslt) (list (list (pop rslt) (pop rslt))))))
+              rslt)
+   :orgn `(FINITE-MODEL-SPHERE ,dmns)))
+
+
+(DEFMETHOD FINITE-SUSPENSION ((topogenous matrice))
+  #| Non-Hausdorff suspension of 'topogenous' |#
+  (let* ((nlig+1 (1+ (nlig topogenous)))
+         (rslt (add-points topogenous nlig+1 2)))
+    (maj-colonne rslt nlig+1 (loop for x in (<a-b> 1 nlig+1)
+                                   collect (list x 1)))
+    (maj-colonne rslt (1+ nlig+1) (loop for x in (<a-b> 1 (1- nlig+1))
+                                        collect (list x 1)))
+    (insert-term rslt (1+ nlig+1) (1+ nlig+1) 1)
+    rslt))
+
+
+(DEFMETHOD FINITE-SUSPENSION ((finspace finite-space))
+  (build-finite-space :top (finite-suspension (top finspace))
+                      :orgn `(FINITE-SUSPENSION ,(idnm finspace))))
diff --git a/src/homology-groups.lisp b/src/homology-groups.lisp
index efc1e4b..d2049bf 100644
--- a/src/homology-groups.lisp
+++ b/src/homology-groups.lisp
@@ -185,8 +185,8 @@
 (defun terme (mat i j)
   (let ((p (left (chercher-hor (baselig mat i) j))))
     (if (= j (icol p))
-        (val (left p))
-        nil)))
+        (val p)
+        0)))
 
 (defun mat-aleat (n1 n2 dens x)
   (let ((mat (creer-matrice n1 n2))
diff --git a/src/kenzo.fas b/src/kenzo.fas
new file mode 100755
index 0000000..c2396a5
Binary files /dev/null and b/src/kenzo.fas differ