ordered set bounded below是什么意思

用法例句

It is proved that such discontinuous problems has infinitely many eigenvalues and the eigenvalues are boundary from below.

把正则Sturm-Liouville问题关于特征值的性质推广到一类带转移条件的Sturm-Liouville问题中,利用prüfer变换证明了具有分离边界条件的这类问题有无穷多个实特征值,且特征值是下方有界的。