C. Lang

activity

20132021

most citedFibonacci Numbers and Identities II

7 citations · 11 across the 15 of their papers we have counts for

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4 papers · 1 filter

math.GR2015

Arithmetic and geometry of the Hecke groups

Cheng Lien Lang, Mong Lung Lang

We study the arithmetic and geometry properties of the Hecke group $G_{q}$ . In particular, we prove that $G_{q}$ has a subgroup $X$ of index $d$ , genus $g$ with $v_{\infty}$ cusps, a…

math.GR2014

Commutator subgroup of the Hecke group $G_{5}$ is not congruence

Cheng Lien Lang, Mong Lung Lang

We prove that the power subgroup $G_{5}^{5}$ and the commutator subgroup $G_{5}^{'}$ of the Hecke group $G_{5}$ are not congruence.

math.GR2014★ 2 cited

Wohlfahrt's Theorem for the Hecke group G_5

Cheng Lien Lang, Mong Lung Lang

Let K be a subgroup of the inhomogeneous Hecke group G_5 of finite index. Suppose that the geometric level of K is r. Then K is congruence if and only if K contains the principal c…

math.GR2014

The index formula for the Hecke group H_5

Cheng Lien Lang, Mong Lung Lang

The present article gives the index formula of the principal congruence subgroups of the Hecke group H_5

Arithmetic and geometry of the Hecke groups

Commutator subgroup of the Hecke group G5​ is not congruence

Wohlfahrt's Theorem for the Hecke group G_5

The index formula for the Hecke group H_5

Commutator subgroup of the Hecke group $G_{5}$ is not congruence