Re: Inverse????

*To*: mathgroup at smc.vnet.net*Subject*: [mg5499] Re: [mg5477] Inverse????*From*: Daniel Lichtblau <danl>*Date*: Sat, 14 Dec 1996 19:26:04 -0500*Organization*: wolfram.com*Sender*: owner-wri-mathgroup at wolfram.com

Hou-shou Chen wrote: > > A matrix a={{0,0,1},{0,0,1},{1,1,1}} which is singular in Z_2, but > Inverse commands gives the "result": > > Inverse[a,Modulus->2]= > {{0, 1, 1}, {1, 1, 0}, {1, 0, 0}}. > > Is anything wrong ? > > Houshou Yes. It was a bug. Fixed in version 3.0. In[5]:= a={{0,0,1},{0,0,1},{1,1,1}}; In[6]:= Det[a, Modulus->2] Out[6]= 0 In[7]:= Inverse[a,Modulus->2] Inverse::sing: Matrix {{0, 0, 1}, {0, 0, 1}, {1, 1, 1}} is singular. Out[7]= Inverse[{{0, 0, 1}, {0, 0, 1}, {1, 1, 1}}, Modulus -> 2] Daniel Lichtblau Wolfram Research danl at wolfram.com