Dear Shubh, If you are using GAP 4.5, then the answer is yes. In the Citrus package ( http://www-groups.mcs.st-andrews.ac.uk/~jamesm/citrus/index.html) you can find the command Factorization which does what you want. For example,
gap> f:=RandomTransformation(7); Transformation( [ 6, 4, 2, 3, 4, 3, 1 ] ) gap> g:=RandomTransformation(7); Transformation( [ 1, 6, 4, 4, 7, 4, 6 ] ) gap> M:=Monoid(f,g); <monoid with 2 generators> gap> h:=Random(M); Transformation( [ 1, 6, 4, 4, 7, 4, 6 ] ) gap> Factorization(M, h); [ 2 ] gap> h:=Random(M); Transformation( [ 6, 3, 3, 3, 1, 3, 3 ] ) gap> Factorization(M, h); [ 2, 1 ] gap> g*f; Transformation( [ 6, 3, 3, 3, 1, 3, 3 ] ) gap> h:=Random(M); Transformation( [ 1, 4, 4, 4, 6, 4, 4 ] ) gap> Factorization(M, h); [ 2, 2 ] gap> h:=Random(M); Transformation( [ 4, 4, 4, 4, 4, 4, 4 ] ) gap> Factorization(M, h); [ 1, 1, 2, 1, 2 ] gap> f^2*g*f*g; Transformation( [ 4, 4, 4, 4, 4, 4, 4 ] ) The list that is returned is a list of positive integers where i corresponds to GeneratorsOfSemigroups(S)[i]. Regards, James Date: Tue, 24 Jan 2012 16:54:58 +0530 From: sh...@iitg.ernet.in To: fo...@gap-system.org Subject: [GAP Forum] Combination of generators Message-ID: <fd6edcbdafc85cd9397ac6d0200e8001.squir...@webmail.iitg.ernet.in> Content-Type: text/plain;charset=iso-8859-1 Dear Sir, I have a finitely generated transformation monoid M on a finite set X generated by two transformations f and g on X. Also I have another transformation h in M. Is there any method to tell what type of combination of f and g give h. With Regards, Shubh -- Shubh N. Singh Research Scholar Department of Mathematics IIT Guwahati - 781039 Email: sh...@iitg.ernet.in Mob. no.: +91-9864221370 -- James Mitchell tinyurl.com/jdmitchell The University of St Andrews is a charity registered in Scotland : No SC013532 _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum