incr-set prlevel 1
if #0=4 START
incr-set prlevel -1
;;; Usage:
;;; 	<smoothness r i hyp sing 
;;;
;;; 	r ring of P4, i ideal of a suface in P4,
;;;	computes hyp the ideal of the non hypersurface singularity locus of i
;;;	and sing the singular locus of i
;;;
incr-set prlevel 1
jump END
;;; Parameters:
;;;
;;; Output values:
;;;
;;; (discussion)
;;;
;;; Caveats:
;;;
; created 92FOS.
START:
copy #2 @i
jacob @i @di
flat @di @hyp
std @hyp #3
deg #3 @codim @sing
if @codim<5 END
;only hypersurface singularities
shout deg #3
wedge @di 2 @min
flat @min @sing
kill @min 
concat @sing @i
std @sing #4
codim #4 @codim @deg
if @codim<5 END
incr-set prlevel -1
;smooth
codim #4
codim #3
incr-set prlevel 1
kill @i @di @sing @hyp @codim @deg
END:

incr-set prlevel -1
$;;;;;;;; EXAMPLE SECTION ;;;;;;;;;;;;;;;;;;;;;;;;;
