Building a matrix

To build a matrix, you may type it as usual with { and } instead of [ and ] or you may use one of the following instructions:

• idn: to build a symbolic identity matrix I_n (if n is at level 1)
• LCXM: to build a matrix $A=(a_{ij})_{1\leq i \leq l, 1 \leq j \leq c}$. The command takes 3 arguments: l, c and a program building a_ij from i and j. Example: 2 4 << SQ + >> LCXM returns a $2\times 4$ matrix with a_ij=i+j².
• VAND and HILBERT return Vandermonde and Hilbert matrices given respectively a list of objects or an integer.