# ExtElement ExtElement -- multiplication of Ext-algebra elements

## Synopsis

• Operator: SPACE
• Usage:
u=x y
• Inputs:
• x, an instance of the type ExtElement, $x$ is of type $E$, where $E$ is of type ExtAlgebra
• y, an instance of the type ExtElement, $y$ is of type $E$
• Outputs:
• u, an instance of the type ExtElement, $u$ is of type $E$, the Ext-algebra product of $x$ and $y$

## Description

SPACE is used as infix notation for the Ext-algebra multiplication, which is graded commutative.

 i1 : L = lieAlgebra{a,b,c}/{a b,b c} o1 = L o1 : LieAlgebra i2 : E = extAlgebra(3,L) o2 = E o2 : ExtAlgebra i3 : (ext_1+2 ext_0) ext_2 o3 = - ext_3 o3 : E