# zero: The zero polynomial

## Description

Test for the zero, or empty, polynomial

## Usage

zero(d)
is.zero(L)
is.empty(L)

## Arguments

L

A two-element list of indices and values, possibly a spray
object

d

Integer specifying dimensionality of the spray (the arity)

## Details

Functions `is.empty()`

and `is.zero()`

are synonyms. If spray
objects are interpreted as multivariate polynomials,
“`is.zero()`

” is more intuitive, if sprays are interpreted
as sparse arrays, “`is.empty()`

” is better (for me).

## Examples

# NOT RUN {
a <- lone(1,3)
is.zero(a-a) # should be TRUE
is.zero(zero(6))
x <- spray(t(0:1))
y <- spray(t(1:0))
is.zero((x+y)*(x-y)-(x^2-y^2)) # TRUE
# }