Twin positive solutions of nonlinear first-order boundary value problems on time scales

In this paper we consider the following nonlinear first-order boundary value problem on time scale TT: {xΔ(t)=f(x(σ(t))),t∈[0,T]T,x(0)=βx(σ(T)), where 0<β<10<β<1. Some existence criteria for at least two positive solutions are established by using the well-known twin-fixed-point theorem due to Avery and Henderson.