Keivan Mallahi-Karai

activity

20122026

most citedFuture exchange rates and Siegel's paradox

3 citations · 4 across the 17 of their papers we have counts for

collaborators

24 papers

math.CO2026

On the Dimension of the Best-Worst Choice Polytope

Keivan Mallahi-Karai, Majid Salamat

For a set of $n$ alternatives, the best--worst choice polytope is the convex hull of the deterministic best--worst choice vectors induced by all linear rankings of the alternatives…

math.CO2026

An infinite family of trees with irreducible characteristic polynomials

Saieed Akbari, Keivan Mallahi-Karai

Consider the tree obtained by attaching a leaf to the third vertex of a path with n-1 vertices. In this note, we prove that the characteristic polynomial of this tree is irreducibl…

math.PR2026

Random free semigroups of affine groups

Richard Aoun, Keivan Mallahi-Karai

We investigate random freeness of semigroups in the solvable non-virtually nilpotent setting. We focus on a correlated affine model, namely semigroups generated by the two componen…

math.CO2025

Counting $F_{q}$ -points of orbital varieties in ad-nilpotent ideals of type $A_{n}$

Mohammad Bardestani, Keivan Mallahi-Karai, Samrith Ram +1

Let $b_{n} (F_{q})$ denote the Lie algebra of upper triangular $n \times n$ matrices over the finite field $F_{q}$ , and let $u_{n} (F_{q})$ be the ni…

math.GR2024

Spectral Independence

Alireza S Golsefidy, Keivan Mallahi-Karai, Amir Mohammadi

We prove the spectral gap property for random walks on the product of two non-locally isomorphic analytic real or p-adic compact groups with simple Lie algebras, under the necessar…

math.DS2022

On an extreme value law for the unipotent flow on $SL_{2} (R) / SL_{2} (Z)$

Maxim Kirsebom, Keivan Mallahi-Karai

We study an extreme value distribution for the unipotent flow on the modular surface $SL_{2} (R) / SL_{2} (Z)$ . Using tools from homogenous dynamics and…

math.GN2022

Compactifications of horospheric products

Behrang Forghani, Keivan Mallahi-Karai

We define and study a new compactification, called the height compactification of the horospheric product of two infinite trees. We will provide a complete description of this comp…

math.GR2022

Polynomiality of the faithful dimension of nilpotent groups over finite truncated valuation rings

Mohammad Bardestani, Keivan Mallahi-Karai, Dzmitry Rumiantsau +1

The faithful dimension of a finite group $G$ over $C$ , denoted by $m_{faithful} (G)$ , is the smallest integer $n$ such that $G$ can be embedde…

math.GR2021

Optimal Linear Sofic Approximations Of Countable Groups

Keivan Mallahi-Karai, Maryam Mohammadi Yekta

A countable group G is called k-linear sofic (for some 0 <k \le 1) if finite subsets of G admit "approximate representations" by complex invertible matrices in the normalized rank…

math.DS2021

Asymptotic distribution for pairs of linear and quadratic forms at integral vectors

Jiyoung Han, Seonhee Lim, Keivan Mallahi-Karai

We study the joint distribution of values of a pair consisting of a quadratic form $q$ and a linear form $l$ over the set of integral vectors, a problem initiated by Dani-M…

math.GR2020

Locally Random Groups

Keivan Mallahi-Karai, Amir Mohammadi, Alireza Salehi Golsefidy

In this work, we will introduce and study the notion of local randomness for compact metric groups. We prove a mixing inequality as well as a product result for locally random grou…

q-fin.MF2018★ 3 cited

Future exchange rates and Siegel's paradox

Keivan Mallahi-Karai, Pedram Safari

Siegel's paradox is a fundamental question in international finance about exchange rates for futures contracts and has puzzled many scholars for over forty years. The unorthodox ap…

math.GR2018

Some applications of arithmetic groups in cryptography

Delaram Kahrobaei, Keivan Mallahi-Karai

In this paper we will give various examples of exponentially distorted subgroups in linear groups, including some new example of subgroups of $S L_{n} (Z [x])$ for $n \geq 3$ , a…

math.RT2017

Kirillov's orbit method and polynomiality of the faithful dimension of $p$ -groups

Mohammad Bardestani, Keivan Mallahi-Karai, Hadi Salmasian

Given a finite group $G$ and a field $K$ , the faithful dimension of $G$ over $K$ is defined to be the smallest integer $n$ such that $G$ embeds into $\ma…

math.CO2017

Polynomial configurations in sets of positive upper density over local fields

Mohammad Bardestani, Keivan Mallahi-Karai

Let $F (x) = (f_{1} (x), \dots, f_{m} (x))$ be such that $1, f_{1}, \dots, f_{m}$ are linearly independent polynomials with real coefficients. Based on ideas of Bachoc, DeCorte, Oliveira and Va…

math.CO2016

Amenability of trees

Behrang Forghani, Keivan Mallahi-Karai

We will give a criterion for the amenability of arbitrary locally finite trees. The criterion is based on the trimming operator which is defined on the space of trees. As an applic…

math.PR2016

Positive harmonic functions of transformed random walks

Behrang Forghani, Keivan Mallahi-Karai

In this paper, we will study the behavior of the space of positive harmonic functions associated with the random walk on a discrete group under the change of probability measure by…

math.DS2016

Distribution of orbits of unipotent groups on S-arithmetic homogeneous spaces

Keivan Mallahi-Karai

We will prove an S-arithmetic version of a theorem of Dani-Margulis on the convergence of ergodic averages of a given bounded continuous function, when the initial point is outside…

math.DS2016★ 1 cited

Asymptotic distribution of values of isotropic quadratic forms at $S$ -integral points

Jiyoung Han, Seonhee Lim, Keivan Mallahi-Karai

We prove an analogue of a theorem of Eskin-Margulis-Mozes: suppose we are given a finite set of places $S$ over $Q$ containing the archimedean place and excluding the prim…

math.CO2015

On a generalization of the Hadwiger-Nelson problem

Mohammad Bardestani, Keivan Mallahi-Karai

For a field $F$ and a quadratic form $Q$ defined on an $n$ -dimensional vector space $V$ over $F$ , let $QG_{Q}$ , called the quadratic graph associated to $Q$ , be the graph wi…

math.RT2015

Minimal dimension of faithful representations for $p$ -groups

Mohammad Bardestani, Keivan Mallahi-Karai, Hadi Salmasian

For a group $G$ , we denote by $m_{f ai t h f u l} (G)$ , the smallest dimension of a faithful complex representation of $G$ . Let $F$ be a non-Archimedean local field with the ring of integ…

math.GR2014

Faithful representations of Chevalley groups over quotient rings of non-Archimedean local fields

Mohammad Bardestani, Camelia Karimianpour, Keivan Mallahi-Karai +1

Let $F$ be a non-Archimedean local field with the ring of integers $O$ and the prime ideal $p$ and let $G = G (O / p^{n})$ be th…

math.GR2013

On the Erdos-Ko-Rado property for finite Groups

Mohammad Bardestani, Keivan Mallahi-Karai

Let a finite group $G$ act transitively on a finite set $X$ . A subset $S \subseteq G$ is said to be {\it intersecting} if for any $s_{1}, s_{2} \in S$ , the element $s_{1}^{- 1} s_{2}$ has a fix…

math.GR2012

Quasi-Random profinite groups

Mohammad Bardestani, Keivan Mallahi-Karai

We will investigate quasi-randomness for profinite groups. We will obtain bounds for the mininal degree of non-trivial representations of $\mathrm{SL}_k(\mathbb{Z}/(p^n\mathbb{Z}))…

On the Dimension of the Best-Worst Choice Polytope

An infinite family of trees with irreducible characteristic polynomials

Random free semigroups of affine groups

Counting Fq​-points of orbital varieties in ad-nilpotent ideals of type An​

Spectral Independence

On an extreme value law for the unipotent flow on SL2​(R)/SL2​(Z)

Compactifications of horospheric products

Polynomiality of the faithful dimension of nilpotent groups over finite truncated valuation rings

Optimal Linear Sofic Approximations Of Countable Groups

Asymptotic distribution for pairs of linear and quadratic forms at integral vectors

Locally Random Groups

Future exchange rates and Siegel's paradox

Some applications of arithmetic groups in cryptography

Kirillov's orbit method and polynomiality of the faithful dimension of p-groups

Polynomial configurations in sets of positive upper density over local fields

Amenability of trees

Positive harmonic functions of transformed random walks

Distribution of orbits of unipotent groups on S-arithmetic homogeneous spaces

Asymptotic distribution of values of isotropic quadratic forms at S-integral points

On a generalization of the Hadwiger-Nelson problem

Minimal dimension of faithful representations for p-groups

Faithful representations of Chevalley groups over quotient rings of non-Archimedean local fields

On the Erdos-Ko-Rado property for finite Groups

Quasi-Random profinite groups

Counting $F_{q}$ -points of orbital varieties in ad-nilpotent ideals of type $A_{n}$

On an extreme value law for the unipotent flow on $SL_{2} (R) / SL_{2} (Z)$

Kirillov's orbit method and polynomiality of the faithful dimension of $p$ -groups

Asymptotic distribution of values of isotropic quadratic forms at $S$ -integral points

Minimal dimension of faithful representations for $p$ -groups