志強的數學題

Clear["Global`*"] (*Clear all variables*)
(*
下面計算一個代數,把代數定義成爲一個函數,而後給函數賦予attribute.

*)

f[x1, x1] := x0 + a1 x1 + x2
f[x1, x2] := x1 + a2 x2 + x3
f[x1, x3] := x2 + a3 x3 + x4
f[x1, x4] := x3 + a4 x4

SetAttributes[f, Orderless]

f[x1, x1]

 

x0 + a1 x1 + x2

Set::write: Tag TensorProduct in x1\[TensorProduct]x1 is Protected.

x0 + a1 x1 + x2

x1\[TensorProduct]x1