Hi Henning, Yes I just realised my mistake myself - I hand over the function instead of the result. A really facinating concept by the way. Thanks again for the Matrix notation - will give it a go right away now. And the "manoever critics" on the code is really nice. - Helps me a lot to embrace the haskell syntax. One thing that still confuses me a litte: polynom: double -> double ->double polynom x y = y^2 + x^2 + 2*x*y Type declaration for this polynom with two inputs - what is input and what is output and which way a I supposed to read it ? -- x,y,polynom ? and when would I use double -> double => double Is there by the way the possibility in haskell to create functions with several outputs - ala Matlab function declation: function [N,k] = histogram(v,n) Hope I'm not asking too basic questions here, so feel free to point me to the right tutorial. Cheers Phil -- View this message in context: http://haskell.1045720.n5.nabble.com/Matlab-Style-Logic-Operations-ala-V1-V2... Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.