The paper proposes a method for constructing a sparse estimator for the
inverse covariance (concentration) matrix in high-dimensional settings. The
estimator uses a penalized normal likelihood approach and forces sparsity by
using a lasso-type penalty. We establish a rate of convergence in the Frobenius
norm as both data dimension $p$ and sample size $n$ are allowed to grow, and
show that the rate depends explicitly on how sparse the true concentration
matrix is. We also show that a correlation-based version of the method exhibits
better rates in the operator norm. We also derive a fast iterative algorithm
for computing the estimator, which relies on the popular Cholesky decomposition
of the inverse but produces a permutation-invariant estimator. The method is
compared to other estimators on simulated data and on a real data example of
tumor tissue classification using gene expression data.

提出一种构建稀疏估计器的方法，用于高维背景下的逆协方差（浓度）矩阵，使用罚函数正态似然方法强制使用 Lasso 型惩罚，并在数据维数 $p$ 和样本量 $n$ 随着增长收敛速率之间建立 Frobenius 范数。同时对真实浓度矩阵进行稀疏度量，提出一种基于相关性的方法，在操作规范下具有更好的收敛速率，推出一种快速迭代算法用于计算估计值，利用常用的 Cholesky 分解反演，得到一种置换不变的估算法，文中将这种方法应用于癌症组织分类的基因表达数据上，并与其他估算方法进行了比较。