Paper:
Regularization is known to be an inexpensive and reasonable solution to alleviate the overfitting problem arising in inference models, including deep neural networks. In this paper, we propose hierarchical regularization which preserves the semantic structure of a sample distribution. At the same time, this regularization promotes diversity by imposing a distance between parameter vectors enlarged within semantic structures. To generate evenly distributed parameters which is considered less redundant, we constrain them to lie on hierarchical hyperspheres. To define a hierarchical parameter space, we propose to reformulate the topology space with multiple hyperspheres. On each hypersphere, a projection is parameterized by two individual parameters. Since maximizing a groupwise and pairwise distance between points on hypersphere is nontrivial (generalized Thomson problem), we propose a new discrete metric integrated with a continuous metric. The proposed method shows improved generalization performance on extensive experiments using publicly available datasets (CIFAR-10, CIFAR-100, CUB200-2011, and Stanford Cars), especially when the number of super-classes is large.

Review:
The paper proposes a hierarchical regularization framework based on hierarchical hyperspheres. In particular, the paper tackles the problem of diversity promoting learning. Following (Liu et al., 2018), pairwise distances between parameters on hyperspheres are used in the regularization framework.
The topology of the parameter space is reformulated with multiple hypersphere spaces which are each defined by two parameters: the centroid of a sphere and its surface vector. Multiple strategies involving hierarchical hyperspherical structures are proposed in Section 3 (continuous and discrete). 
The relevance of the proposed method is experimentally demonstrated on different computer vision datasets.
I vote for reject for the following reasons:
- The paper is hard to read in general. Although the method section is understandable, its readability could be improved because each method currently just looks like a succession of equations. The paper also does not really give an intuition of why (or what contexts) one of the proposed regularizers would be better than the others. 
- The reported (test accuracy) scores do not seem significantly better than the l2 baseline: none of the reported scores beats the l2 baseline by at least 1 percent, and it is unclear how that difference is measurable. How many splits/different initalizations were used? Why not give standard deviation over different test splits? etc... Given the fact that the improvements do not seem significant compared to a single baseline, a proper evaluation with standard deviation should be provided.
- Although the paper cites (Liu et al., 2018) as motivation for their framework, why does the proposed method does not compare to the other related work (i.e. works by Xie)?
As a side note, the paper seems to motivate the use of multiple spherical spaces to represent hierarchies. Recent work in machine learning has shown the advantage of using hyperbolic geometry [A,B] to represent trees, hence hierarchies. 
[A] Nickel and Kiela, Poincaré Embeddings for Learning Hierarchical Representations, NIPS 2017
[B] Ganea et al., Hyperbolic Neural Networks, NeurIPS 2018
======= after the rebuttal
I have read carefully the updated manuscript, other reviews and rebuttal.
My score does not change since the proposed method does not seem to improve much compared to a simple weight decay (baseline + l2 regularization). The motivation of using the method for a very small improvement is not convincing. The "well-defined hierarchical information which is categorized by an expert as mentioned in the manuscript" can also be exploited by hyperbolic representations and should then also be compared (as baseline).