I was trying to do some noncommutative Ext-computations and got unexpected results. The following is a minimal example (where everything is actually commutative):

**Code:**

LIB "nchomolog.lib";

ring base = 0,(x,y),dp;

def A = nc_algebra(1,0); setring A;

ideal i = (x,y);

ncExt_R(0,i);

=> _[1,1]=1

ncExt_R(1,i);

=> _[1]=x*gen(1)

ncExt_R(2,i);

=> _[1]=gen(1)

I'm reading this as Ext^i_{k[x,y]}(k, k[x,y]) = 0 for i != 1 and Ext^1 = k[y]. But this is clearly no the correct result. Am I misunderstanding something? Ext_R from homolog.lib gives me the correct Ext's (i.e. Ext^2 = k, everything else vanishes).

I was trying to do some noncommutative Ext-computations and got unexpected results. The following is a minimal example (where everything is actually commutative):

[code]

LIB "nchomolog.lib";

ring base = 0,(x,y),dp;

def A = nc_algebra(1,0); setring A;

ideal i = (x,y);

ncExt_R(0,i);

=> _[1,1]=1

ncExt_R(1,i);

=> _[1]=x*gen(1)

ncExt_R(2,i);

=> _[1]=gen(1)

[/code]

I'm reading this as Ext^i_{k[x,y]}(k, k[x,y]) = 0 for i != 1 and Ext^1 = k[y]. But this is clearly no the correct result. Am I misunderstanding something? Ext_R from homolog.lib gives me the correct Ext's (i.e. Ext^2 = k, everything else vanishes).