ɪf dʌznˌɑːt kəntˈeɪn pˈiː, wˈaɪ hɐz nˈoʊ ɐkjˌuːmjʊlˈeɪʃən pˈɔɪnt bɪkˈʌz wˈaɪ ɪz klˈoʊzd ɪn ˈɛks ænd dɪskɹˈiːt ɪnðə sˈʌbspeɪs təpˈɑːlədʒi.
If  does not contain p, Y has no accumulation point (because Y is closed in X and discrete in the subspace topology).