             if debug { Swift.print(msg()) }
         }
         
-        for I0 in base.mDegrees {
+        for I0 in mDegrees {
             let I1 = I0 + dDegree
             let I2 = I1 + dDegree
             

        return d.mDegree
    }
    
    public func shifted(_ I: IntList) -> ChainComplexN<n, A, R> {
        return ChainComplexN(base: base.shifted(I), differential: d.shifted(I))
    }

        }
    }
    
    public var bidegrees: [(Int, Int)] {
        return base.bidegrees
    }
    
    public func shifted(_ i: Int, _ j: Int) -> ChainComplex2<A, R> {
        return shifted(IntList(i, j))
    }
