# sum

From freegroup v1.1-0
by Robin K S Hankin

##### Repeated summation by concatenation

Concatenates its arguments to give a single free object

##### Usage

```
# S3 method for free
sum(..., na.rm = FALSE)
```

##### Arguments

- …
Objects of class

`free`

, to be summed- na.rm
Boolean, indicating whether to ignore

`NA`

entries (currently ignored)

##### Details

Concatenates its arguments and gives a single element of the free
group. It works nicely with `rev()`

, see the examples.

##### Examples

```
# NOT RUN {
x <- rfree(10,3)
y <- rfree(10,6)
z <- alpha(26)
sum(x)
abelianize(sum(x))
sum(x,y) == sum(sum(x),sum(y))
x+y # not the same!
sum(x,-x)
sum(x,rev(-x))
stopifnot(sum(x^z) == sum(x)^z)
# }
```

*Documentation reproduced from package freegroup, version 1.1-0, License: GPL-2*

### Community examples

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