Answer: Suppose that [tex]S_{n}[/tex], [tex]K_{n}[/tex] and [tex]A_{n}[/tex] are all sequences, also suppose that [tex]A_{n}[/tex] ⊂ [tex]K_{n}[/tex] ⊂ [tex]S_{n}[/tex] ∀ [tex]n[/tex] ∈ [tex]Z^{+}[/tex]. This implies that [tex]A_{n}[/tex] ⊂ [tex]S_{n}[/tex] as required.
Step-by-step explanation:
If you suppose that [tex]S_{n}[/tex], [tex]K_{n}[/tex] and [tex]A_{n}[/tex] are all representing three sequences respectively, and you also suppose that [tex]A_{n}[/tex] is a subset (in other words subsequence) of [tex]K_{n}[/tex] and [tex]K_{n}[/tex] is a subset (in other words subsequence) of [tex]S_{n}[/tex], where n takes its values from the set of positive integers. We can safely say that [tex]A_{n}[/tex] is a subsequence of [tex]S_{n}[/tex] and this can demosnstrated mathematically as follows:
Suppose that [tex]S_{n}[/tex], [tex]K_{n}[/tex] and [tex]A_{n}[/tex] are all sequences, also suppose that [tex]A_{n}[/tex] ⊂ [tex]K_{n}[/tex] ⊂ [tex]S_{n}[/tex] ∀ [tex]n[/tex] ∈ [tex]Z^{+}[/tex]. This implies that [tex]A_{n}[/tex] ⊂ [tex]S_{n}[/tex] as required.