`expansion``.project(tape)`¶

An expansion that keeps only the selected tape of the original expansion.

Preconditions:

the original expression is multitape.
the tape number is smaller than the number of tapes.

Examples¶

In [1]:

import vcsn
ctx = vcsn.context("lat<lan_char(ab), lan_char(cd), lan_char(ef)>, q")

In [2]:

x = ctx.expression("a*|c|[ef]").expansion()
x

Out[2]:

$\varepsilon|c|e \odot \left[\varepsilon\right] \oplus \varepsilon|c|f \odot \left[\varepsilon\right] \oplus a|c|e \odot \left[ \left. {a}^{*} \middle| \varepsilon \middle| \varepsilon \right. \right] \oplus a|c|f \odot \left[ \left. {a}^{*} \middle| \varepsilon \middle| \varepsilon \right. \right]$

In [3]:

x.project(0)

Out[3]:

$\left\langle 2\right\rangle \oplus a \odot \left[\left\langle 2\right\rangle {a}^{*}\right]$

In [4]:

x.project(1)

Out[4]:

$c \odot \left[\left\langle 4\right\rangle \varepsilon\right]$

In [5]:

x.project(2)

Out[5]:

$e \odot \left[\left\langle 2\right\rangle \varepsilon\right] \oplus f \odot \left[\left\langle 2\right\rangle \varepsilon\right]$