id	sid	tid	token	lemma	pos
f1881j94n03	1	1	recently	recently	ADV
f1881j94n03	1	2	,	,	PUNCT
f1881j94n03	1	3	there	there	PRON
f1881j94n03	1	4	has	have	AUX
f1881j94n03	1	5	been	be	AUX
f1881j94n03	1	6	significant	significant	ADJ
f1881j94n03	1	7	political	political	ADJ
f1881j94n03	1	8	interest	interest	NOUN
f1881j94n03	1	9	in	in	ADP
f1881j94n03	1	10	developing	develop	VERB
f1881j94n03	1	11	sustainable	sustainable	ADJ
f1881j94n03	1	12	energy	energy	NOUN
f1881j94n03	1	13	in	in	ADP
f1881j94n03	1	14	the	the	DET
f1881j94n03	1	15	united	united	PROPN
f1881j94n03	1	16	states	states	PROPN
f1881j94n03	1	17	.	.	PUNCT
f1881j94n03	2	1	this	this	DET
f1881j94n03	2	2	paper	paper	NOUN
f1881j94n03	2	3	first	first	ADV
f1881j94n03	2	4	outlines	outline	VERB
f1881j94n03	2	5	the	the	DET
f1881j94n03	2	6	practical	practical	ADJ
f1881j94n03	2	7	constraints	constraint	NOUN
f1881j94n03	2	8	and	and	CCONJ
f1881j94n03	2	9	considerations	consideration	NOUN
f1881j94n03	2	10	in	in	ADP
f1881j94n03	2	11	moving	move	VERB
f1881j94n03	2	12	away	away	ADV
f1881j94n03	2	13	from	from	ADP
f1881j94n03	2	14	fossil	fossil	ADJ
f1881j94n03	2	15	fuels	fuel	NOUN
f1881j94n03	2	16	.	.	PUNCT
f1881j94n03	3	1	then	then	ADV
f1881j94n03	3	2	,	,	PUNCT
f1881j94n03	3	3	taking	take	VERB
f1881j94n03	3	4	these	these	DET
f1881j94n03	3	5	constraints	constraint	NOUN
f1881j94n03	3	6	into	into	ADP
f1881j94n03	3	7	account	account	NOUN
f1881j94n03	3	8	,	,	PUNCT
f1881j94n03	3	9	we	we	PRON
f1881j94n03	3	10	develop	develop	VERB
f1881j94n03	3	11	a	a	DET
f1881j94n03	3	12	basic	basic	ADJ
f1881j94n03	3	13	model	model	NOUN
f1881j94n03	3	14	of	of	ADP
f1881j94n03	3	15	energy	energy	NOUN
f1881j94n03	3	16	production	production	NOUN
f1881j94n03	3	17	with	with	ADP
f1881j94n03	3	18	varying	vary	VERB
f1881j94n03	3	19	levels	level	NOUN
f1881j94n03	3	20	of	of	ADP
f1881j94n03	3	21	pollution	pollution	NOUN
f1881j94n03	3	22	in	in	ADP
f1881j94n03	3	23	discrete	discrete	ADJ
f1881j94n03	3	24	time	time	NOUN
f1881j94n03	3	25	.	.	PUNCT
f1881j94n03	4	1	we	we	PRON
f1881j94n03	4	2	reduce	reduce	VERB
f1881j94n03	4	3	the	the	DET
f1881j94n03	4	4	model	model	NOUN
f1881j94n03	4	5	to	to	ADP
f1881j94n03	4	6	a	a	DET
f1881j94n03	4	7	system	system	NOUN
f1881j94n03	4	8	of	of	ADP
f1881j94n03	4	9	integral	integral	ADJ
f1881j94n03	4	10	equations	equation	NOUN
f1881j94n03	4	11	.	.	PUNCT
f1881j94n03	5	1	under	under	ADP
f1881j94n03	5	2	appropriate	appropriate	ADJ
f1881j94n03	5	3	assumptions	assumption	NOUN
f1881j94n03	5	4	,	,	PUNCT
f1881j94n03	5	5	the	the	DET
f1881j94n03	5	6	solutions	solution	NOUN
f1881j94n03	5	7	to	to	ADP
f1881j94n03	5	8	the	the	DET
f1881j94n03	5	9	equations	equation	NOUN
f1881j94n03	5	10	are	be	AUX
f1881j94n03	5	11	the	the	DET
f1881j94n03	5	12	optimal	optimal	ADJ
f1881j94n03	5	13	level	level	NOUN
f1881j94n03	5	14	of	of	ADP
f1881j94n03	5	15	pollution	pollution	NOUN
f1881j94n03	5	16	and	and	CCONJ
f1881j94n03	5	17	energy	energy	NOUN
f1881j94n03	5	18	production	production	NOUN
f1881j94n03	5	19	in	in	ADP
f1881j94n03	5	20	the	the	DET
f1881j94n03	5	21	economy	economy	NOUN
f1881j94n03	5	22	.	.	PUNCT
f1881j94n03	6	1	it	it	PRON
f1881j94n03	6	2	is	be	AUX
f1881j94n03	6	3	unknown	unknown	ADJ
f1881j94n03	6	4	,	,	PUNCT
f1881j94n03	6	5	however	however	ADV
f1881j94n03	6	6	,	,	PUNCT
f1881j94n03	6	7	if	if	SCONJ
f1881j94n03	6	8	these	these	DET
f1881j94n03	6	9	equations	equation	NOUN
f1881j94n03	6	10	can	can	AUX
f1881j94n03	6	11	be	be	AUX
f1881j94n03	6	12	solved	solve	VERB
f1881j94n03	6	13	.	.	PUNCT
f1881j94n03	7	1	hence	hence	ADV
f1881j94n03	7	2	,	,	PUNCT
f1881j94n03	7	3	we	we	PRON
f1881j94n03	7	4	pose	pose	VERB
f1881j94n03	7	5	the	the	DET
f1881j94n03	7	6	problem	problem	NOUN
f1881j94n03	7	7	in	in	ADP
f1881j94n03	7	8	continuous	continuous	ADJ
f1881j94n03	7	9	time	time	NOUN
f1881j94n03	7	10	,	,	PUNCT
f1881j94n03	7	11	which	which	PRON
f1881j94n03	7	12	yields	yield	VERB
f1881j94n03	7	13	an	an	DET
f1881j94n03	7	14	analogous	analogous	ADJ
f1881j94n03	7	15	system	system	NOUN
f1881j94n03	7	16	of	of	ADP
f1881j94n03	7	17	differential	differential	ADJ
f1881j94n03	7	18	equations	equation	NOUN
f1881j94n03	7	19	.	.	PUNCT
f1881j94n03	8	1	the	the	DET
f1881j94n03	8	2	traditional	traditional	ADJ
f1881j94n03	8	3	approaches	approach	NOUN
f1881j94n03	8	4	used	use	VERB
f1881j94n03	8	5	to	to	PART
f1881j94n03	8	6	solve	solve	VERB
f1881j94n03	8	7	these	these	DET
f1881j94n03	8	8	equations	equation	NOUN
f1881j94n03	8	9	have	have	AUX
f1881j94n03	8	10	failed	fail	VERB
f1881j94n03	8	11	.	.	PUNCT
f1881j94n03	9	1	solving	solve	VERB
f1881j94n03	9	2	this	this	DET
f1881j94n03	9	3	equation	equation	NOUN
f1881j94n03	9	4	is	be	AUX
f1881j94n03	9	5	the	the	DET
f1881j94n03	9	6	next	next	ADJ
f1881j94n03	9	7	step	step	NOUN
f1881j94n03	9	8	towards	towards	ADP
f1881j94n03	9	9	developing	develop	VERB
f1881j94n03	9	10	rigorous	rigorous	ADJ
f1881j94n03	9	11	models	model	NOUN
f1881j94n03	9	12	in	in	ADP
f1881j94n03	9	13	mathematical	mathematical	ADJ
f1881j94n03	9	14	finance	finance	NOUN
f1881j94n03	9	15	.	.	PUNCT