26 Recursion •Some phrasal categories may appear to the left or right of the arrow NP ⇒(DET) N (PP) PP ⇒P (NP) Recursion: the property that allows for a phrase to generate another phrase of same category (either directly or via repeated rule application) – This can yield infinitely long phrases/sentences
27 Recursion •Recursion:– See "Recursion".
Recursion 28 Optional reading: pp 8 and 9 of ‘Words and Rules’ by Steve Pinker (on course website)
NP DET N PP a frog P NP on DET N PP the log P NP in DET N PP the hole P NP on DET N PP the bottom P NPof DET N the sea29 NP ⇒DET N (PP) PP ⇒P NP ?v=CjwLvieUbf8#t=00m16s… [NPa frog [PPon [NPthe log [PPin [NPthe hole [PPon [NPthe bottom [PPof [NPthe sea]]]]]]]]]…
Next Time •HW 3 (Moodle) due at noontoday •Part I of Class Project is available on website •HW 4 (Moodle) available on Monday 2/4 •When there are no clicker questions, everyone gets a participation point for that day 30