The proofs of Theorems 2.1, 2.2 and 2.3 from [Olatinwo M.O., Some results on multi-valued weakly jungck mappings in b-metric space, Cent. Eur. J. Math., 2008, 6(4), 610–621] base on faulty evaluations. We give here correct but weaker versions of these theorems.
It is proved that under some conditions the set of solutions to initial value problem for second order functional differential system on an unbounded interval is a compact -set and hence nonvoid, compact and connected set in a Fréchet space. The proof is based on a Kubáček’s theorem.
We study best approximation in -normed spaces via a general common fixed point principle. Our results unify and extend some known results of Carbone [ca:pt], Dotson [do:bs], Jungck and Sessa [ju:at], Singh [si:at] and many of others.