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Terminal: run. Derivation Graphs: (left-to-right) compact / full; (top-down) full / compact.

Help: blue = parse inside. Abbr.: WS: Workspace; Initial WS: initial heads for Merge after LEX lookup.

WS n, n = 1,2,... for intermediate stages after Initial WS. Final WS: when WS items converge on a single SO.
Bracketing: {...} (Merge). {...} (FormSet). At Spellout, {...} indicates free word order. [word] indicates word is optionally present.
Head Hd_{selection/features}, e.g. p_θ = predicate head p that seeks a θ-relevant (θR) IA from the WS. p_θ is a θ-seeker (θS).
v_see:θ:pst = head v has complement see, a θR EA from the WS and TNS. v is also a θS.
INFL seeks θR from its complement (not the WS).
Complementizer C comes in different flavors wrt. Force, .e.g. declarative C, interrogative C_Q and relative clause head C_rel.
Features, e.g. TNS pres/pst or DET the/a (shorthand for a bundle of semantic features).
Note: φ-features, e.g. 1sg, appear only at Spellout. Some words do not project, turn into features, e.g. determiners.

Words: the mechanic fixed the car

Initial WS 1: car_the fix_θ v_fix:_θ:_pst INFL_v mechanic_the

WS 1: {fix_θ, car_the} v_fix:_θ:_pst INFL_v mechanic_the

WS 2: {v_fix:_θ:_pst, {fix_θ, car_the}} INFL_v mechanic_the

WS 3: {mechanic_the, {v_fix:_θ:_pst, {fix_θ, car_the}}} INFL_v

WS 4: {INFL_v, {mechanic_the, {v_fix:_θ:_pst, {fix_θ, car_the}}}}

Final WS: {C, {INFL_v, {mechanic_the, {v_fix:_θ:_pst, {fix_θ, car_the}}}}}

INT/EXT: {C, {INFL_v, {mechanic_the, {v_fix:_θ:_pst, {fix_θ, car_the}}}}}

EXT: the mechanic 3sg pst fix the car

Spellout: the mechanic fixed the car

Parse found: the mechanic 3sg pst fix the car

WS 1: {fix_θ, mechanic_the} car_the v_fix:_θ:_pst INFL_v

WS 2: {v_fix:_θ:_pst, {fix_θ, mechanic_the}} car_the INFL_v

WS 1: {car_the, mechanic_the} fix_θ v_fix:_θ:_pst INFL_v

WS 2: {fix_θ, {car_the, mechanic_the}} v_fix:_θ:_pst INFL_v

WS 3: {v_fix:_θ:_pst, {fix_θ, {car_the, mechanic_the}}} INFL_v