cartanMatrix(RootSystem) -- the Cartan matrix of a root system

Synopsis

• Function: cartanMatrix

• Usage:

  cartanMatrix(R)

• Inputs:
  • R, an instance of the type RootSystem,
• Outputs:
  • a matrix, the Cartan matrix of R

Description

i1 : R=rootSystemA(3)

o1 = RootSystem{...8...}

o1 : RootSystem

i2 : cartanMatrix R

o2 = | 2  -1 0  |
     | -1 2  -1 |
     | 0  -1 2  |

              3        3
o2 : Matrix ZZ  <--- ZZ