Functions on Lazy Series Rings

Lazy series rings have variables, names for their variables and a coefficient ring.

R . i : RngPowLaz, RngIntElt -> RngPowLazElt
The ith variable of the lazy power series ring R, where i is between 1 and the rank of R.
AssignNames(~R, S) : RngPowLaz, [MonStgElt] ->
Given a lazy series ring R with n indeterminates and a sequence S of n strings, assign the elements of S to the names of the variables of R.
BaseRing(R) : RngPowLaz -> Rng
CoefficientRing(R) : RngPowLaz -> Rng
The coefficient ring of the lazy power series ring R. The coefficients of all the series in R will lie in this ring.
Rank(R) : RngPowLaz -> RngIntElt
The number of variables associated with the lazy power series ring R.
R1 eq R2 : RngPowLaz, RngPowLaz -> BoolElt
Return true if the lazy series rings R1 and R2 are the same ring, that is, they have the same coefficient ring and rank.

Example RngLaz_ring-ops (H51E2)

The functions on lazy power series rings are illustrated here. 
> L := LazyPowerSeriesRing(FiniteField(73), 7);
> L.4;
Lazy power series
> AssignNames(~L, ["a", "b", "c", "d", "fifth", "sixth", "seventh"]);
> L.4;
Lazy power series
The names for the variables of L are not used in default series printing. However they are used when printing an element to a given precision using PrintToPrecision. 
> CoefficientRing(L);
Finite field of size 73
> Rank(L);
7
> L eq LazyPowerSeriesRing(CoefficientRing(L), Rank(L));
true
V2.28, 13 July 2023