1. Introduction
In 1988, Hamilton [
1] originally proposed the concept of Ricci flow. A Ricci soliton can be described as the limit reached by solutions of this flow. Additionally, significant attention has recently been directed towards classifying solutions that exhibit self-similarity within geometric flows.
In 2011, the immersed almost Ricci solitons on Riemannian manifolds were examined in [
2]. The authors discovered that within a Riemannian manifold 
 possessing a non-positive sectional curvature, 
 cannot be minimal, as an almost Ricci soliton is identical to a Ricci soliton, and an integrable norm on 
 is maintained by the vector field 
V. Furthermore, Wylie [
3] explained that compactness is a necessary property of a Riemannian manifold with a shrinking soliton. Additionally, these immersions lack minimality if 
 is characterized by a non-positive sectional curvature.
Cunha et al. [
4] employed the Newton transformation 
 alongside the second-order differential operator 
, for the range 
, to formulate the concept of the 
r-almost Newton–Ricci soliton (ANRS) in Riemannian manifolds. De et al. [
5] and Siddiqi [
6,
7] also discussed the same concept on Lagrangian submanifolds and Legendrian submanifolds.
The conformal Ricci flow, an enhancement of the classical Ricci flow, was introduced by Fischer in [
8]. This geometric flow modifies the equation’s unit volume constraint, replacing it with a scalar curvature constraint. The formula for conformal Ricci flow on a Riemannian manifold 
 is given by the following:
      where 
P denotes a non-dynamical scalar field (time-dependent scalar field), 
S denotes the Ricci tensor, 
 is the scalar curvature, and 
n is the dimension of the manifold 
.
Einstein metrics with the Einstein constant are the steady states of the equations of conformal Ricci flow. The de-Turck method was used by Lu et al. [
9] to reconstruct the conformal Ricci flow in terms of concrete parabolic elliptic PDEs. They explain the transient presence of the conformal Ricci flow on both asymptotically flat and compact manifolds.
In 2015, Basu and Bhattacharyya [
10] introduced the notion of a conformal Ricci soliton. The corresponding equation is as follows:
Here,  denotes the Lie derivative operator along the vector field F, and  represents a real constant. P is a non-dynamical scalar field, S denotes the Ricci tensor, and n is the dimension of the manifold .
If 
 meets (
2), it is classified as a conformal Ricci soliton on 
M [
10]. Based on 
, 
, or 
, 
 will exhibit the following:
- (i)
- Shrinking; 
- (ii)
- Steady; 
- (iii)
- Expanding, respectively. 
If the vector field 
F in (
2) is a gradient vector field associated with a smooth function 
, then we obtain the conformal gradient Ricci soliton by using mathematical operators as in [
11].
On the other hand, on a manifold, the polynomial structures were considered in [
12], which served as the foundation of the golden structure [
13]. Ref. [
14] provided insight into integrability within the Riemannian manifold with a golden structure. The golden sectional curvature was recently studied in [
15]. The same authors also examined the geometry of submanifolds within locally decomposable Golden Riemannian manifolds with constant golden sectional curvature.
In [
16], the authors conceptualized the metallic structure in 2013, a generalization of the golden structure established on Riemannian manifolds. The researchers in [
17,
18,
19,
20,
21,
22] addressed various aspects of the metallic Riemannian manifolds regarding curvature.
The literature on almost Ricci solitons, shrinking solitons, and related subjects in Riemannian manifolds and Lagrangian submanifolds serves as inspiration for the current work. In this study, we analyze k-almost Newton-conformal Ricci solitons on a hypersurface within a Golden Riemannian manifold with constant golden sectional curvature. It is the first investigation of such solitons on a hypersurface of a Golden Riemannian manifold with constant golden sectional curvature.
  2. Golden Riemannian Manifolds
Consider a 
-tensor field 
 on a manifold 
. Then 
 is a golden structure on 
 if [
12,
23]
In this case, 
 is called a golden manifold. Additionally, a Riemannian manifold 
 having a golden structure 
 fulfilling
      is said to be a Golden Riemannian manifold [
13]. Substituting 
 with 
 in (
4), we have
When
      the Golden Riemannian manifold 
 becomes locally decomposable.
Let 
 be a locally decomposable Golden Riemannian manifold with constant golden sectional curvature 
c. Subsequently, we obtain [
15]
      for every vector field 
 and 
 on 
.
Consider a connected submanifold defined by
Then, the Gauss equation is written as [
24]
, where the Riemannian curvature tensors of 
 and 
 are 
 and 
R, respectively.
Consider an orthonormal frame  on  and denote the Hilbert–Schmidt norm of .
Recall that on 
, the scalar curvature 
r is given by [
15]
      where 
 denotes the mean curvature vector and
Furthermore, the golden scalar curvature 
 corresponding to the golden sectional curvature of the submanifold 
 in 
 is expressed by [
15]
  3. -Almost Newton-Conformal Ricci Soliton
We remark that 
 is a linked and oriented hypersurface immersed in an 
-dimensional Golden Riemannian manifold possessing a uniform golden sectional curvature. Let 
 be the 
k-th Newton transformation
      described by the recursive relationship:
      for the identity operator 
 and 
. Here, 
 indicates the composition of 
 with itself 
j times, i.e., 
.
We call 
 a 
k-almost Newton-conformal Ricci soliton (ANCRS) if, for each 
, there exists
      such that,
In this context, 
 and 
 are smooth functions defined on 
. The tensor field 
 is given by
.
When 
, (
8) simplifies to a gradient almost conformal Ricci soliton. The second fundamental form 
 of 
 possesses 
n algebraic invariants, identified as elementary symmetric functions, 
, derived from principal curvatures 
. In immersion, 
k-th mean curvature 
 can be expressed as follows:
      where 
 is the binomial coefficient, and 
 is the 
k-th elementary symmetric polynomial given by
Putting  we obtain , the mean curvature of .  denotes the trace operator.
Moreover, it follows that the characteristic polynomial of 
 is given by
The Laplacian operator 
 can be obtained for 
. We also recall that
      where
If the ambient space has constant sectional curvatures, Equation (
9) takes on this form
      as 
 (see [
25]).
The traceless second fundamental form of the hypersurface is
      and
 is totally umbilical if and only if
Example 1. 
         We consider the usual immersion of  in , known to be totally geodesic. Here, , . By selecting, , an immersion that satisfies (8) can be obtained.  Example 2. 
         Let  be the unit sphere in the Euclidean space  andthe embedding with induced metric g on ; then  is a Riemannian manifold with sectional curvature . Let  be an immersion of an n-dimensional manifold  into a smooth unit sphere.
According to [26], with a constant , select the functions  on  such thatwhere  is the position vector and , , . We get that  holds for However,  is known to be totally umbilical, having a second fundamental form  and a k-th mean curvature . More specifically, the Newton tensor for each  is provided byaccording to which Therefore, by using the smooth function , we can obtain the Equation (8), which describes the hypersurface. Furthermore, if  has constant scalar curvature, (8) can be simplified by using mathematical operators as follows:. For a further illustration of a gradient r-almost Newton–Einstein soliton, see Example 2 in [4].    4. Main Results
We will use the maximum principle [
27] to prove our results. First, we fix
.
We also use the subsequent result [
25]:
Lemma 1. 
         Consider  to be an oriented, non-compact, complete Riemannian manifold, and a smooth vector field U on it. The divergence  maintains a uniform sign throughout . If the magnitude  belongs to , then it follows that  must be zero.
 Theorem 1.2 of [
26] can be further generalized as follows:
Theorem 1. 
         Suppose  is a complete ANCRS on  in  with constant golden sectional curvature r and bounded . If
- (i) 
- , , and , implies that  is not minimal; or 
- (ii) 
- , , and , implies that  is not minimal; or 
- (iii) 
- when , with , and ,  is minimal and isometric to . 
Here,  denotes the potential function with 
 Proof.  From (
9), it is clear that the type of 
 is divergent. Since the second fundamental form is bounded on 
, Equation (
7) implies that 
 has a bounded norm
On the other hand, assume that 
 is minimal to demonstrate (1) and (2). Using (
5) with 
, we find that 
 is fulfilled by 
. Therefore, the contraction of (
8) implies
        in both cases. This contradicts Lemma 1. This finishes the proof of (1) and (2).
Next, because 
 has constant sectional curvature 
 and using the minimality of 
, (
5) reduces to
But, 
 and 
. Then, in view of Lemma 1, we deduce that
One concludes that
        proving that 
 is totally geodesic and flat.    □
 Corollary 1. 
         Suppose all considerations of Theorem 1 are true and the golden scalar curvature  of  is expressed in terms of the golden sectional curvature and . Then
- (i) 
- , ,  is not minimal. 
- (ii) 
- , ,  fails to be minimal. 
- (iii) 
- , ,  is minimal and isometrically equivalent to . 
 The conclusion coming next and related to Theorem 3 of [
28] is necessary for establishing our results.
Lemma 2. 
         Let  be complete, endowed with a subharmonic function u that is non-negative and smooth. For , u is constant if .
 Additionally, we have
Theorem 2. 
         Let  be a complete ANCRS on  in , which has constant golden sectional curvature r and . If
- (i) 
- , , then  is not minimal; 
- (ii) 
- , , then  is not minimal; 
- (iii) 
- , , and  is minimal, then  is flat and totally geodesic. 
In this context,  is regarded as non-negative and belongs to  for , while  is assumed to be upper-bounded when considering quadratic forms.
 Proof.  The starting point to demonstrate (1) is to consider the contradiction that 
 is minimal in relation to (
5) and the hypothesis 
. The contraction of (
8) yields
Assuming that 
 is bounded from above, there exists a positive constant that fulfills
		As a result, we argue that 
 is constant through Lemma 2, which is not expected. One is likely to acquire (2) and (3) by employing an identical process to Theorem 1.    □
 Corollary 2. 
         Assume the hypotheses of Theorem 2 are true, and the golden scalar curvature  of  is expressed in terms of the golden sectional curvature and .
- (i) 
- ,  implies  is not minimal; 
- (ii) 
- ,  implies  is not minimal; 
- (iii) 
- , , and  being a minimal manifold imply that  is necessarily flat and totally geodesic. 
 We extend Theorem 1.5 of [
2] for 
 in our subsequent result. We also give the conditions for an ANCRS on a hypersurface 
 of 
 with golden scalar curvature 
 corresponding to the golden sectional curvature to be totally umbilical, assuming 
 possesses a bounded second fundamental form. Consequently, we derive the following:
Theorem 3. 
         For , consider  a complete ANCRS situated on the hypersurface , possessing a uniform golden sectional curvature r, characterized by its golden sectional curvature, with a bounded second fundamental form. Consequently,
- (i) 
- , then  is totally geodesic with - and the scalar curvature is given by 
- (ii) 
- then  is isometric to a Euclidean sphere. 
- (iii) 
-  is totally umbilical with 
Here,  represents the potential function with 
 Proof.  By using (
8) and (
5), we derive
It is evident that on 
, 
 is a non-negative function for our study on 
. According to Lemma 1, 
 vanishes identically. Consequently, 
 is totally geodesic from (
11), and we get
Moreover, it is clear from (
5) that
        which establishes (1).
Given its totally geodesic nature, the ambient space will take the form of a sphere 
 (if 
 is compact). Furthermore, 
 is isometric to 
, i.e., (2). As a consequence of (
11), we get
Consequently, it follows from our assumption on 
 that
So, from Lemma (1), it follows that one has
This demonstrates the totally umbilical nature of . □
 Corollary 3. 
         Suppose that the hypotheses of Theorem 3 are true and  of  is expressed in terms of the golden sectional curvature. Then
- (i) 
-  is totally geodesic with 
- (ii) 
- is isometric to a Euclidean sphere; 
- (iii) 
-  is totally umbilical provided 
   5. Compact Gradient ANCRS
A few natural outcomes, assuming  is constant, and that a compact ANCRS on the hypersurface  of  serves as the foundation for the main conclusions drawn in this section. Furthermore, the subsequent lemmas provide final results.
Lemma 3 
         ([
25])
. Let  be non-compact and the support of ψ be compact, or  be compact without a boundary. Then- (i) 
- , 
- (ii) 
hold.
 Dealing with the known traceless second fundamental form of 
 in 
, referred to as 
, will serve our objectives. Note that
      and
      with equality holding if and only if 
 is totally umbilical.
We review Yau’s Lemma, which relates to Theorem 3 of [
28], to finish this section.
Lemma 4. 
         Let u be a non-negative, smooth subharmonic function on the complete Riemannian manifold . If u belongs to  for some , then u is necessarily a constant.
 For every 
, we denote
Theorem 4. 
         Let  be a compact gradient ANCRS immersed in a Golden Riemannian manifold  with constant golden sectional curvature r, such that  is bounded from above or from below (in the sense of quadratic forms). If any of the below conditions are true,
- (i) 
- either  and  and  or  and ; or 
- (ii) 
-  and  and  or  and ; or 
- (iii) 
- either  or , 
then  has to be trivial and of constant scalar curvature. Here,  (in the sense of quadratic forms) is bounded from above or below.
 Proof.  Consequently, when (i) or (ii) holds, one discovers
        and (
8) yields
Given that 
 has upper and lower bounds, there exists a constant 
 to ensure
        respectively. Therefore, the function 
 is subharmonic. By Hopf’s theorem, one can infer that 
 is a constant function because 
 is compact. As a result, 
 is trivial.
Subsequently, (iii) follows exactly in the same way as (i) and (ii).    □
 Theorem 5. 
         Consider a compact gradient ANCRS  immersed in , which has constant golden sectional curvature r, such that  is bounded from above or from below and . Then,  is trivial in case  has constant golden sectional curvature.
 Proof.  Lemma 3 and (
8) allow us to write
By assuming that  has upper or lower bounds, we continue as in the proof of Theorem 4 to get that  is trivial.    □
 Moving on, we derive the subsequent corollaries based on Theorems 4 and 5.
Corollary 4. 
         Let all the hypotheses of Theorem 4 hold, and the golden scalar curvature  of  is expressed corresponding to the golden sectional curvature. If any of the below statements holds
- (i) 
- either  with  and , or  and ; or 
- (ii) 
- , coupled with  and , or  and ; or, 
- (iii) 
-  is either greater than or equal to , or less than or equal to , 
then  has constant golden scalar curvature  and is trivial.
 Proof.  Since the ambient space has constant golden sectional curvature, by Equation (
10), the operator 
 is a divergent type. Regarding (i) and (ii), Equation (
6) jointly with assumption 
  implies that golden scalar curvature 
 of 
 satisfies 
 (
 Thus, from (
8), we have
        in both cases, which contradicts Lemma 1. Hence, 
 that is,
		This completes the proof of the assertions.    □
 Corollary 5. 
         Assuming the hypotheses of Theorem 5 are valid and the golden scalar curvature  of  aligns with the golden sectional curvature, then if  has a constant golden sectional curvature,  is trivial.
 Proof.  In view of (
6), Lemma 3, and (
8), we can easily prove the corollary.    □
   6. Some Applications
The Schur inequality [
29], typically associated with positive real numbers, has generalizations and extensions to various mathematical contexts, including Riemannian manifolds and submanifolds. In this context, it relates quantities like sectional curvature, mean curvature, and scalar curvature of a submanifold to those of the ambient manifold. These inequalities provide insights into the geometry of submanifolds and their relationships with the surrounding space. Some Schur-type inequalities relate the mean curvature of a submanifold to its average value.
For example, Schur-type inequalities on sub-static manifolds and sub-static submanifolds naturally arise in general relativity [
7].
The classical Schur’s lemma states that the scalar curvature of an Einstein manifold of dimension  must be constant. The applications of k-th mean curvatures of closed hypersurfaces in space forms and k-scalar curvatures for closed locally conformally flat manifolds can be expressed in terms of Schur-type inequalities involving the Ricci scalar. Moreover, Schur-type inequalities appear more generally in general relativity in relation to the so-called null convergence condition with Ricci and scalar curvature.
It was recently shown by De Lellis and Topping [
29] that a closed Riemannian manifold satisfies
The average of 
r over Riemannian manifolds 
 is indicated by the symbol 
. Furthermore, if and only if 
 is Einstein, the equality holds in the inequality (
12).
We prove a Schur-type inequality in terms of k-almost Newton-conformal Ricci solitons immersed in Golden Riemannian manifolds with constant golden sectional curvature.
Theorem 6. 
         Consider a compact gradient ANCRS  immersed in a Golden Riemannian manifold  with constant golden sectional curvature r, such that  is bounded from above or from below and . Thenwhere  is the traceless Ricci tensor, and  stands for the average of r on .  Proof.  We recall from the contracted Bianchi identity that
        and, hence, that
		Since 
 is compact, using our assumption on 
, we get the following:
        where we used 
. Since 
 is compact, we have
Therefore,
        or equivalently,
        i.e.,
This completes the proof.    □
 Remark 1. 
         Observe that in the above theorem, if 
 is Einstein, then both sides of (
13) vanish, so the equality holds. It would be an interesting problem to prove the rigidity.
 Similarly, we turn up the Schur-type inequality for k-almost Newton-conformal Ricci solitons immersed in Golden Riemannian manifolds with golden scalar curvature.
Corollary 6. 
         Consider a compact gradient ANCRS  immersed in a Golden Riemannian manifold  with golden scalar curvature , such that  is bounded from above or from below and . Then