 Following the work of the second author with Raghavendra and Vempala, wherein the complexity of \lambda_\infty was related to the so-called Small-Set Expansion (SSE) problem, it has been believed that computing \lambda_\infty is a hard problem.
<fluency>  Following the work of the second author with Raghavendra and Vempala, wherein the complexity of \lambda_\infty was related to the so-called Small-Set Expansion (SSE) problem, it has been believed that computing \lambda_\infty is a hard problem.
 Following the work of the second author with Raghavendra and Vempala, wherein the complexity of \lambda_\infty was related to the so-called small-set expansion (SSE) problem, it has been believed that computing \lambda_\infty is a hard problem.