Copy(p) returns a copy of p. If p is subsequently modified (for example by computing extra coefficients, or modifying the display style), these changes are not reflected in p, and vice versa.  Note that p and its copy may share ancestors, that is, power series from which p was computed.

Copy(u) returns a copy of u, constructed from copies of the coefficients of u. The coefficients of u and its copy may share ancestors.

When using the MultivariatePowerSeries package, do not assign anything to the variables occurring in the power series and univariate polynomials over power series. If you do, you may see invalid results.

$\mathrm{with}\left(\mathrm{MultivariatePowerSeries}\right)\:$

$a≔\mathrm{Inverse}\left(\mathrm{PowerSeries}\left(1+x-y\right)\right)\:$

$b≔\mathrm{Inverse}\left(\mathrm{PowerSeries}\left(y^2-x+1\right)\right)\:$

$c≔a+b$

$c≔\left[\mathrm{Pow\ⅇrS\ⅇri\ⅇs\; of}\frac{1}{1+x-y}+\frac{1}{y^2-x+1}\mathrm{:}2+\mathrm{\dots }\right]$

$d≔\mathrm{Copy}\left(c\right)$

$d≔\left[\mathrm{Pow\ⅇrS\ⅇri\ⅇs\; of}\frac{1}{1+x-y}+\frac{1}{y^2-x+1}\mathrm{:}2+\mathrm{\dots }\right]$

$\mathrm{SetDisplayStyle}\left(c\,\left['\mathrm{precision}'=7\right]\right)$

$\left[\mathrm{precision}=7\right]$

$\mathrm{SetDisplayStyle}\left(d\,\left['\mathrm{precision}'=4\right]\right)$

$\left[\mathrm{precision}=4\right]$

$\mathrm{UpdatePrecision}\left(c\,7\right)\:$$\mathrm{UpdatePrecision}\left(d\,7\right)\:$

$c$

$\left[\mathrm{Pow\ⅇrS\ⅇri\ⅇs\; of}\frac{1}{1+x-y}+\frac{1}{y^2-x+1}\mathrm{:}2+y+2x^2-2xy+3x^{2}y-5y^{2}x+y^3+2x^4-4x^{3}y+3x^2{y}^2-4x{y}^3+2y^4+5x^{4}y-14x^3{y}^2+10x^2{y}^3-2x{y}^4+y^5+2x^6-6x^{5}y+10x^4{y}^2-20x^3{y}^3+21x^2{y}^4-6x{y}^5+7x^{6}y-27x^5{y}^2+35x^4{y}^3-25x^3{y}^4+21x^2{y}^5-11x{y}^6+y^7+\mathrm{\dots }\right]$

$d$

$\left[\mathrm{Pow\ⅇrS\ⅇri\ⅇs\; of}\frac{1}{1+x-y}+\frac{1}{y^2-x+1}\mathrm{:}2+y+2x^2-2xy+3x^{2}y-5y^{2}x+y^3+2x^4-4x^{3}y+3x^2{y}^2-4x{y}^3+2y^4+\mathrm{\dots }\right]$

$\mathrm{gc}\left(\right)\:$

$\mathrm{CodeTools}:-\mathrm{Usage}\left(\mathrm{HomogeneousPart}\left(c\,500\right)\right)\:$

memory used=143.48MiB, alloc change=115.65MiB, cpu time=2.41s, real time=2.23s, gc time=408.37ms

$\mathrm{Precision}\left(a\right)$

$500$

$\mathrm{Precision}\left(b\right)$

$500$

$\mathrm{Precision}\left(c\right)$

$500$

$\mathrm{Precision}\left(d\right)$

$7$

$\mathrm{gc}\left(\right)\:$

$\mathrm{CodeTools}:-\mathrm{Usage}\left(\mathrm{HomogeneousPart}\left(d\,500\right)\right)\:$

memory used=6.70MiB, alloc change=0 bytes, cpu time=45.00ms, real time=46.00ms, gc time=0ns

$\mathrm{Precision}\left(d\right)$

$500$

The MultivariatePowerSeries[Copy] command was introduced in Maple 2021.

For more information on Maple 2021 changes, see Updates in Maple 2021.