An Implementable Semantics for Comparative Constructions

ion (X, Qlfl ),Store) "-raise_comparative (Qlf0, Q1 fl, Store ) . raise_comparative (quant (Det0, Cn item), quant (Detl, Cn_it era),Store) --ralse_ccmparative (Det 0, Detl, Store) . raise cc~paratlve (quant (Det, cn (Head, [Mod0] ) ), quant (Det, cn (Head, [Modl] ) ),Store) "-raise_comparative (Mod0,Modl, Store). raise_cc~paratlve (role (Role, Quant0 ),role (Role, Quantl ),Store) '-raise_cc~parative (Quant0, Quantl, Store) . raise_ccmparative (subject (Quant0), subject (Quant i },Store) •-raise_comparative (Quant 0, Quant I, Store). raise comparative (vp (Head, X, Qlf0 ), vp (Head, X, Qlfl ),Store) •-raise_comparative (Qlf0, Qlfl, Store) . rewrlte ql f_on sabtrees (apply (Np,Vp0), apply (Np, Vp) ) :-rewrite_q1 f (Vp0, Vp) .rewrite_q1 f_on_sabtrees (apply (Np0, Vp), apply (Np,V~) ) :-rewrite_qlf (Np0, Np) . rewrite ql f_on subtrees (vp (Head, X, Qlf0 ), vp (Head, X, Q1 f ) ) :-rewrite qlf (Qlf0, Qlf). rewrite qlf_on subtrees ( IF0 iR), (F JR] ) :-rewrite qlf (F0, F) .rewrite_ql f_on_subtrees ( [F IR0], [F IR) ) :-rewrite_qlf (R0, R) . rewrit e_ql f_on_subtrees (role (Role, Quant 0 ), role (Role, Quant ) ) :-rewrite qlf (Quant O, Quant ). rewrite_ql f_on_sabtrees (sub Ject (Quant0), sub Ject (Quant) ) :-rewrite_q1 f (Quant 0, Quant ) . rewrite_qlf on_sabtrees (quant (Det, Cn0 ), quant (Det, Cn) ) :-rewrite_qlf (Cn0, Cn) . rewrite ql f_on_subtrees (cn (Head, Mods0 ), cn (Head, Mods ) ) :-rewrite_qlf (Mods0,Mods) . % find_contrast checks a Ccomplement against something that might% be a contrastable item (or contain one). The last three arguments are: what% the thing is replaced by (either the C, or some thlng containing the C), % the extracted contrasted item, and a pointer to the C. Note that the% contrast cannot contain the Q hence the following clause. Computational Linguistics Volume 16, Number 2, June 1990107 Manny Rayner and Amelie BanksAn ImplementableSemantics for ComparativeConstructions findcont rast 0 [C_cccnple~nent,Q1 f 0, Q1 f, Contrast, C, Q) :-find_contrast (C_complement, Qlf0, Qlf, Contrast, C),\+contains_id(Contrast,Q). % There are a large n~m~ber of cases. It would clearly be possible to collapse% at least some of these. % The first five are essentially slmilar: % i: we're looking at a role, and the C complement is also a role.% (John has more books in the bec~rocm than in the kitchen) flnd_contrast (role (Role,_),role (Role, Quant ),C, role (Role, Quant ), C) . % 2: we're looking at a role, and the C_complement is an NP.% (John has more books in the bedroc~ than the kitchen). find_contrast(C_ccmplement,role(~le,C~/ant),role(R~le, C),Quant,C) :-np_denotation(Ccc~nplement). % 3: we're looking at an NP, and the C_con~pleJnent is an NP. find_contrast (C cc~pl~ent,Contrast,C, Contrast,C) :-np_denot ation (Ccc~lement),np_denotation(Contrast). % 4: we're looking at a subject, and the C_cc~aplement is something% that can constrast against the subject's NP.% (John has more books in the kitchen than Mary). flnd_contrast (C complement,subject (Quant), subJect(Q~antl) ,Contrast,C) :-find_contrast (C_c~mplement, Quant, Quant I, Contrast, C) . % 5: we're looking at a subject, and the C_ccraplement is a subject.% (John has more books in the kitchen than Mary does). find_contrast(subject(_),subJect(Quant),subJect(C),Quant,C)° % 6: CN contrasting; we're looking at an NP, and the C_cc~nplement is a cn.% (More men have b(>Dks in the kitchen than wc~en). find contrast(cn(_,_), quant(Det,Cn),quant(Det,C),Cn, C). % 7: VP operator contrasting; we're looking at a subject, and the% C_cc~lement is a vp_operator.% (John has more h~oks in the kitchen than Mary is able to). find contrast(vp_operator(,),subJect(Quant),subJect(C),Quant,c). % 8: Preposition contrasting; we're looking at a role, and the% C_complement is a role marker with a "contrastable" role.% ("more women voted for the pro~sal than against".) find contrast(role_marker(Cc~p_role),role (role marker (Role),Quant),role(C, Quant),rolemarker(RDle),C) :-contrastable_roles(Comp_role,Role). contrastable_roles(X,Y) :-(contrastable_roles_l(X,Y);contrastable roles_l(Y,X)). % One example of a clause defining a contrastable role pair: contrastable_rolesl(for,agalnst). % 9: Recurslve cases: find contrast(C complement,vp(Head, X,Qlf),vp(Head, X,Qlfl),Contrasted, C) :-flnd_contrast(C_ccmplement,Qlf, Qlfl,Contrasted, C).find_contrast(C_ccmplement, apply(Qlf,X),apply(Qlfl,X),Contrasted, C) :-find_co~:rast(qcomplement,Qlf,Qlfl,Contrasted, C). find comlrast (C_complement,apply (X, Qlf ),apply (X, Q1 fl ),Contrasted, C) :-find_contrast (c complement, Qlf, Qlfl, Contrasted, C) . find_contrast (C_complement, IF IR], [F_I nR), Contrast, C) :-find_contrast (Ccomplement, F, F_I, Contrast, C) . findcontrast (C cc~lement, [F IR), [F IR_I ], Contrast, C) :-find_contrast (C_cc(nplement, R, R1, Contrast, C) . % Reduce tllrns the QLF into a logical fo~ by recursively going through it. reduce(X,X) :vat(x),!. reduce(appLy(Fqlf,~g_qlf),LF) :-reduce(Fqlf, F),reduce(~:g_qlf,Arg),apply(F,1~rg,LF). reduce(~gstraction(X,Qlf),k(X, LF)) :-reduce (Qlf, LF). % We have to reduce possible degree arguments to a relation. reduce (rel~.tion (A/g_list 0 ), LF ) :-reduce .az g_llst (Arg_list0, A/g_llst ),LF =.. Azg_list. reduce (conJ(Qlfl,Qlf2),LF) :-reduce(Q~fl,LFl),reduce(Qlf2,LF2), conJoir~([LFl, LF2},LF). reduce(s~Ject(Qlf),LF) :reduce(Qlf, LF). reduce (~lar,t (Det, Cn),l(V~_sem, quant (Det sem, Cn sem, vp_sem) ) ) :-reduce det (Det, Det_sem),reduce '~Cr~,Cn_sem) . % "substitute (x)" denotes the higher-order function IP.P (X).% Our sin~le-mlnded implementation of "apply" can't deal with anything more% complicated than simple substitutions, so this has to be treated as a% special case. reduce (trace_np (X), substitute (x)) . reduce(name(N),substitute(N)). reduce (vp_operator (x, Vp_op), k (X,Vp op_sem) ) :-reduce (Vp _op, Vp_op_s em ) . reduce(cn(Head,[)),k(X, Head rel)) :-Head_tel :=.. [Head, X). reduce(cn(Head,[AdJ_qlf]),LF) :-Head rel =.. [Head, X),reduce(KdJ_glf,AdJLF),conJoin([:%(X,Headrel),Adj_LF],LF). reduce (vp (Head, X, Qlf ), k(X, LF) ) :-reduce vp (QI f, LF, Head, Props-Props) . reduce (trace ~p (X) ,X) . reduce (traces (x), X) . reduce(role_marker(Role),Bole). reduce(s operator (X, Qlf),k[X, LF) ) :-reduce (~if, LF) . % This is the expression (*) in section 3.2 reduce (camparlson (Contrast, C_complement, C_operator, c, Q, Psil ), LF) :-Nl_condition = relation([C_operator,N, Nl]),PSI11 = k(Q,~(C, Psil) ) ,apply (Pslll, q(N1, Nl_condition ), N_condit lon0 ),apply (N condition0, C_complement, N_condition),apply (Psill, q (N, N_cond/tion), Qlf0 ),apply (Qlf0, Contrast, Qlf) ,reduce (QI:~=,LF ) . 108Computational Linguistics Volume 16, Number 2, June 1990 Manny Rayner and Amefie BanksAn ImplementableSemantics for ComparativeConstructions