In mathematics, especially in Lie theory, En is the Kac–Moody algebra whose Dynkin diagram is a bifurcating graph with three branches of length 1, 2 and k, with k = n − 4.
ɪn mˌæθɪmˈæɾɪks, ɪspˈɛʃəli ɪn lˈaɪ θˈiəɹi, ˈɛn ɪz ðə kˈæk mˈuːdi ˈældʒᵻbɹə hˌuːz dˈɪŋkɪn dˈaɪəɡɹˌæm ɪz ɐ bˈaɪfɚkˌeɪɾɪŋ ɡɹˈæf wɪð θɹˈiː bɹˈæntʃᵻz ʌv lˈɛŋθ wˈʌn, tˈuː ænd kˈeɪ, wɪð kˈeɪ ˈiːkwəlz ˈɛn mˈaɪnəs fˈoːɹ.