❯♥✐✈❡rs✐❞❛❞❡ ❋❡❞❡r❛❧ ❘✉r❛❧ ❞❡ P❡r♥❛♠❜✉❝♦
Pr♦❥❡t♦ ❡ ❆♥á❧✐s❡ ❞❡ ❆❧❣♦r✐t♠♦s
●r❛❢♦s
Pr♦❢✳ ❚✐❛❣♦ ❇✉❛rq✉❡ ❆ss✉♥çã♦ ❞❡ ❈❛r✈❛❧❤♦
❯♥✐❞❛❞❡ ❆❝❛❞ê♠✐❝❛ ❞❡ ●❛r❛♥❤✉♥s ✕ ❯❋❘P❊ ❇❛❝❤❛r❡❧❛❞♦ ❡♠ ❈✐ê♥❝✐❛s ❞❛ ❈♦♠♣✉t❛çã♦
✶✹ ❞❡ ❞❡③❡♠❜r♦ ❞❡ ✷✵✶✽
❘♦t❡✐r♦
✶ ●r❛❢♦
✷ Pr♦♣r✐❡❞❛❞❡s
✸ ❚✐♣♦s
✹ ➪r✈♦r❡s
✺ ●r❛❢♦s ♣❧❛♥❛r❡s
✻ ❈♦❧♦r❛çã♦ ❞❡ ●r❛❢♦s
✼ ❘❡♣r❡s❡♥t❛çã♦ ❞❡ ●r❛❢♦s
❆❧❣✉♠❛s ❛♣❧✐❝❛çõ❡s
• ▲♦❣íst✐❝❛✿
• ❈❛♠✐♥❤♦s ♥♦s ♠❛♣❛s✳
• ●r❛♥❞❡s r❡str✐çõ❡s ♥♦ ❡♥✈✐♦ ❞❡ ♠❡r❝❛❞♦r✐❛s✳ • ❘❡❞❡s s♦❝✐❛✐s✳
• ❇❛♥❝♦s ❞❡ ❞❛❞♦s✳
• ▼♦❞❡❧❛❣❡♠ ❞♦s r❡❧❛❝✐♦♥❛♠❡♥t♦s ♣❛r❛ ✈✐s✉❛❧✐③❛çã♦ ❞❡ ❝♦♥s✉❧t❛s✳ • ❇❛♥❝♦s ♦r✐❡♥t❛❞♦s ❛ ❣r❛❢♦s✳
▲✐♥❦ ❞❛ r❡♣♦rt❛❣❡♠
●r❛❢♦
• ❯♠ ❣r❛❢♦G(V, E) é ❝♦♠♣♦st♦ ♣♦r ❞♦✐s ❡❧❡♠❡♥t♦s✿
✭✐✮ ❯♠ ❝♦♥❥✉♥t♦V =V(G) ❞❡ ✈ért✐❝❡s ✭♦✉ ♥ós✮ ❞❡G✳
✭✐✐✮ ❯♠ ❝♦♥❥✉♥t♦E =E(G) ❞❡ ♣❛r❡s ♥ã♦ ♦r❞❡♥❛❞♦s ❞❡ ✈ért✐❝❡s ❞✐st✐♥t♦s✱ ❝❤❛♠❛❞♦s ❛r❡st❛s ❞❡G✳
• ❖s ✈ért✐❝❡s u ❡v sã♦ ❞✐t♦s ❛❞❥❛❝❡♥t❡s s❡ e∈E✱ e={u, v}.
• u ❡v sã♦ ❞✐t♦s ❡①tr❡♠♦s ❞❡ e✳ • e❝♦♥❡❝t❛u ❛v✳
• eé ✐♥❝✐❞❡♥t❡u ❛v✳
• ❯♠ ♠✉❧t✐❣r❛❢♦ ❞✐❢❡r❡ ❞❡ ✉♠ ❣r❛❢♦ s✐♠♣❧❡s ♣♦r ♣♦ss✉✐r✿ • ❆r❡st❛s ♠ú❧t✐♣❧❛s ❝♦♥❡❝t❛♥❞♦ ♦ ♠❡s♠♦ ♣❛r ❞❡ ✈ért✐❝❡s✳ • ▲❛ç♦s ❝♦♥❡❝t❛♥❞♦ ✉♠ ✈ért✐❝❡ ❛ ❡❧❡ ♠❡s♠♦✳
●r❛✉ ❞❡ ✉♠ ✈ért✐❝❡
• deg(v) é ♦ ❣r❛✉ ❞❡ ✉♠ ✈ért✐❝❡v✱ ✐st♦ é✱ ♦ ♥ú♠❡r♦ ❞❡
❡①tr❡♠✐❞❛❞❡s ❞❡ ❛r❡st❛s q✉❡ ✐♥❝✐❞❡ ♥❛q✉❡❧❡ ♥ó✳
• ❈❛❞❛ ❛r❡st❛ é ❝♦♥t❛❞❛ ❞✉❛s ✈❡③❡s ✭❝❛❞❛ ❡①tr❡♠✐❞❛❞❡ ❞❡ ✉♠❛ ❛r❡st❛✮✳
• ❚❡♦r❡♠❛ s♦❜r❡ ♦s ❣r❛✉s ❞♦s ✈ért✐❝❡s ❡ ♥ú♠❡r♦s ❞❡ ❛r❡st❛s✿ ❛ s♦♠❛ ❞♦s ❣r❛✉s ❞❡ ✉♠ ❣r❛❢♦ é ✐❣✉❛❧ ❛ ❞✉❛s ✈❡③❡s ♦ ♥ú♠❡r♦ ❞❡ ❛r❡st❛s✳
• ❊①❡♠♣❧♦ ✭❛✮✿ deg(A) = 2✱ deg(B) = 3✱deg(C) = 3✱ deg(D) = 2.
• ❊①❡♠♣❧♦ ✭❜✮✿ deg(A) = 2✱deg(B) = 3✱ deg(C) = 3✱
deg(D) = 4. ✭❖ ❧❛ç♦ ❝♦♥t❛ ❞✉❛s ✈❡③❡s✱ ❝❛❞❛ ❡①tr❡♠✐❞❛❞❡ ❝♦♥t❛
✉♠❛ ✈❡③✮✳
• ❱ért✐❝❡ ♣❛r é ❛q✉❡❧❡ q✉❡ t❡♠ ❣r❛✉ ♣❛r✳ • ❱ért✐❝❡ ✐s♦❧❛❞♦ é ❛q✉❡❧❡ q✉❡ t❡♠ ❣r❛✉ ③❡r♦✳
●r❛❢♦s ✜♥✐t♦s ❡ ●r❛❢♦ tr✐✈✐❛❧
• ●r❛❢♦ ✜♥✐t♦
• ❯♠ ♠✉❧t✐❣r❛❢♦ ✜♥✐t♦ t❡♠ ✉♠ ♥ú♠❡r♦ ✜♥✐t♦ ❞❡ ✈ért✐❝❡s ❡ ❛r❡st❛s✳ • ❯♠ ❣r❛❢♦ s✐♠♣❧❡s ❝♦♠ ✉♠ ♥ú♠❡r♦ ✜♥✐t♦ ❞❡ ✈ért✐❝❡s t❛♠❜é♠
t❡rá ✉♠ ♥ú♠❡r♦ ✜♥✐t♦ ❞❡ ❛r❡st❛s✱ ♣♦rt❛♥t♦ é ✜♥✐t♦✳ • ❯♠ ❣r❛❢♦ tr✐✈✐❛❧ t❡♠ ✉♠ ú♥✐❝♦ ✈ért✐❝❡ ❡ ♥❡♥❤✉♠❛ ❛r❡st❛✳
❙✉❜❣r❛❢♦
H(V′, E′)é ✉♠ s✉❜❣r❛❢♦ ❞❡ G(V, E) s❡V′ ⊆V ❡E′ ⊆E✳
●r❛❢♦s ■s♦♠♦r❢♦s
G(V, E) ❡ G∗(V∗, E∗)sã♦ ❞✐t♦s ✐s♦♠♦r❢♦s s❡✿ • ❡①✐st❡f :V →V∗✱
• s❡{u, v} ∈E s❡ ❡ s♦♠❡♥t❡ s❡{f(u), f(v)} ∈E∗✳
❙ã♦ ✐s♦♠♦r❢♦s✿ ❆ ❡ ❘❀ ❋ ❡ ❚❀ ❑ ❡ ❳❀ ▼✱ ❙✱ ❱ ❡ ❩✳
❯♠❛ ❢✉♥çã♦f:A→Bé ❜✐❥❡t♦r❛ q✉❛♥❞♦fé ✐♥❥❡t♦r❛ ❡ s♦❜r❡❥❡t♦r❛✳ ◆❛ ❢✉♥çã♦ ✐♥❥❡t♦r❛✱ t♦❞♦s ♦s ❡❧❡♠❡♥t♦s ❞❛
♣r✐♠❡✐r❛ tê♠ ❝♦♠♦ ✐♠❛❣❡♠ ❡❧❡♠❡♥t♦s ❞✐st✐♥t♦s ❞❛ ♦✉tr❛✳ ❏á ♥❛ ❢✉♥çã♦ s♦❜r❡❥❡t♦r❛✱ t♦❞♦ ❡❧❡♠❡♥t♦ ❞♦
❝♦♥tr❛❞♦♠í♥✐♦ ❞❡ ✉♠❛ ❢✉♥çã♦ é ✐♠❛❣❡♠ ❞❡ ♣❡❧♦ ♠❡♥♦s ✉♠ ❡❧❡♠❡♥t♦ ❞♦ ❞♦♠í♥✐♦ ❞❡ ♦✉tr❛✳
●r❛❢♦s ❍♦♠❡♦♠♦r❢♦s
❉♦✐s ❣r❛❢♦s sã♦ ❤♦♠❡♦♠♦r❢♦s q✉❛♥❞♦ ♣♦❞❡♠ s❡r ♦❜t✐❞♦s ❞♦ ♠❡s♠♦ ❣r❛❢♦ ❞❛ s❡❣✉✐♥t❡ ♠❛♥❡✐r❛✿ ❞✐✈✐❞✐♥❞♦ ❛s ❛r❡st❛s ❞♦ ❣r❛❢♦ ♦r✐❣✐♥❛❧ ❛❞✐❝✐♦♥❛♥❞♦ ✈ért✐❝❡s✳
❈❛♠✐♥❤♦s
• ❯♠ ❝❛♠✐♥❤♦ ❡♠ ✉♠ ♠✉❧t✐❣r❛❢♦ é ✉♠❛ s❡q✉ê♥❝✐❛ ❞❡ ✈ért✐❝❡s ❡ ❛r❡st❛s✱ ♥❛ q✉❛❧ ❝❛❞❛ ❛r❡st❛ei ❝♦♥té♠ ♦s ✈ért✐❝❡s vi−1 ❡ vi✿
v0, e1, v1, e2, v2, . . . , en−1, vn−1, en, vn.
• ❯♠ ❝❛♠✐♥❤♦ s✐♠♣❧❡s é ✉♠ ❝❛♠✐♥❤♦ ♥♦ q✉❛❧ t♦❞♦s ♦s ✈ért✐❝❡s sã♦ ❞✐st✐♥t♦s✳
• ❯♠❛ tr✐❧❤❛ é ✉♠ ❝❛♠✐♥❤♦ ♥♦ q✉❛❧ t♦❞❛s ❛s ❛r❡st❛s sã♦ ❞✐st✐♥t❛s✳
❈❛♠✐♥❤♦s
• ❚❡♦r❡♠❛ s♦❜r❡ ♣❛ss❡✐♦s ❡ ❝❛♠✐♥❤♦s s✐♠♣❧❡s✿ ❡①✐st❡ ✉♠ ❝❛♠✐♥❤♦ ❞❡ ✉♠ ✈ért✐❝❡ u ❛ ✉♠ ✈ért✐❝❡v s❡ ❡ s♦♠❡♥t❡ s❡ ❡①✐st❡
✉♠ ❝❛♠✐♥❤♦ s✐♠♣❧❡s ❞❡u ♣❛r❛ v✳
• ❖✉tr❛ ♥♦♠❡♥❝❧❛t✉r❛ ✏♣❛ss❡✐♦✑ ❂ ❝❛♠✐♥❤♦✱ ✏❝❛♠✐♥❤♦✑ ❂ ❝❛♠✐♥❤♦ s✐♠♣❧❡s✳
• ❖ ❝♦♠♣r✐♠❡♥t♦ ❞♦ ❝❛♠✐♥❤♦ é ♦ ♥ú♠❡r♦ n ❞❡ ❛r❡st❛s✳
• ❙❡ ♥ã♦ ❤♦✉✈❡r ❛♠❜✐❣✉✐❞❛❞❡✱ é ♣♦ssí✈❡❧ ❞❡♥♦t❛r ♦ ❝❛♠✐♥❤♦ ♣♦r ✉♠❛ s❡q✉ê♥❝✐❛ ❞❡ ✈ért✐❝❡s✳
• ❖ ❝❛♠✐♥❤♦ é ❢❡❝❤❛❞♦ s❡ v0 =vn✳
• ❯♠ ❝✐❝❧♦✱ ♦✉k✲❝✐❝❧♦✱ é ✉♠ ❝❛♠✐♥❤♦ ❢❡❝❤❛❞♦ ❞❡ ❝♦♠♣r✐♠❡♥t♦ k≥3 ♥♦ q✉❛❧ t♦❞♦s ♦s ✈ért✐❝❡s sã♦ ❞✐st✐♥t♦s ❡①❝❡t♦ v0 =vn✳
❊①❡r❝í❝✐♦ ■
✶✳ ❚♦❞♦s ♦s ❝❛♠✐♥❤♦s✳ ❋❛ç❛ ✉♠❛ ❧✐st❛ ❞❡ t♦❞♦s ♦s ❝❛♠✐♥❤♦s s✐♠♣❧❡s ❝♦♠ ❡①❛t❛♠❡♥t❡ ✹ ✈ért✐❝❡s ♥♦ ❣r❛❢♦ ❞❡✜♥✐❞♦ ♣❡❧♦s ❛r❝♦s ✼✲✸ ✶✲✹ ✼✲✽ ✵✲✺ ✺✲✷ ✸✲✽ ✷✲✾ ✵✲✻ ✹✲✾ ✷✲✻ ✻✲✹✳ ✭❢♦♥t❡✮
✷✳ ❚♦❞♦s ♦s ❝❛♠✐♥❤♦s✳ ❋❛ç❛ ✉♠❛ ❧✐st❛ ❞❡ t♦❞♦s ♦s ❝❛♠✐♥❤♦s
s✐♠♣❧❡s ❝♦♠ ❡①❛t❛♠❡♥t❡ ✹ ✈ért✐❝❡s ♥♦ ❣r❛❢♦ ♥ã♦✲❞✐r✐❣✐❞♦ ❞❡✜♥✐❞♦ ♣❡❧❛s ❛r❡st❛s ✸✲✼ ✶✲✹ ✼✲✽ ✵✲✺ ✺✲✷ ✸✲✽ ✷✲✾ ✵✲✻ ✹✲✾ ✷✲✻ ✻✲✹✳ ✭❢♦♥t❡✮
✸✳ ❱❡r✐✜❝❛ ♣❛ss❡✐♦✳ ❊s❝r❡✈❛ ✉♠❛ ❢✉♥çã♦ ❜♦♦❧❡❛♥❛
●❘❆P❍❝❤❡❝❦P❛t❤ q✉❡ ✈❡r✐✜q✉❡ s❡ ✉♠❛ ❞❛❞❛ s❡q✉ê♥❝✐❛ s❡q❬✵✳✳❦❪ ❞❡ ✈ért✐❝❡s ❞❡ ✉♠ ❣r❛❢♦ é ✉♠ ♣❛ss❡✐♦✳ ❋❛ç❛ ❞✉❛s ✈❡rsõ❡s ❞❛ ❢✉♥çã♦✿ ✉♠❛ s✉♣õ❡ q✉❡ ♦ ❣r❛❢♦ é ❞❛❞♦ ♣♦r s✉❛ ♠❛tr✐③ ❞❡ ❛❞❥❛❝ê♥❝✐❛s ❡ ♦✉tr❛ s✉♣õ❡ q✉❡ ♦ ❣r❛❢♦ é ❞❛❞♦ ♣♦r s✉❛s ❧✐st❛s ❞❡ ❛❞❥❛❝ê♥❝✐❛✳ ✭❢♦♥t❡✮
❊①❡r❝í❝✐♦ ■■
✹✳ ❱❡r✐✜❝❛ ❝❛♠✐♥❤♦ s✐♠♣❧❡s✳ ❊s❝r❡✈❛ ✉♠❛ ❢✉♥çã♦
●❘❆P❍❝❤❡❝❦❙✐♠♣❧❡P❛t❤ q✉❡ ✈❡r✐✜q✉❡ s❡ ✉♠❛ s❡q✉ê♥❝✐❛ s❡q❬✵✳✳❦❪ ❞❡ ✈ért✐❝❡s ❞❡ ✉♠ ❣r❛❢♦ é ✉♠ ❝❛♠✐♥❤♦ s✐♠♣❧❡s✳ ❆ ❢✉♥çã♦ ❞❡✈❡ ❞❡✈♦❧✈❡r ✲✶ s❡ ❛ s❡q✉ê♥❝✐❛ ♥ã♦ é ✉♠ ❝❛♠✐♥❤♦✱ ✶ s❡ ❛ s❡q✉ê♥❝✐❛ é ✉♠ ❝❛♠✐♥❤♦ s✐♠♣❧❡s✱ ❡ ✵ s❡ ❛ s❡q✉ê♥❝✐❛ é ✉♠ ❝❛♠✐♥❤♦ ♥ã♦ s✐♠♣❧❡s✳ ❋❛ç❛ ❞✉❛s ✈❡rsõ❡s ❞❛ ❢✉♥çã♦✿ ✉♠❛ s✉♣õ❡ q✉❡ ♦ ❣r❛❢♦ é ❞❛❞♦ ♣♦r s✉❛ ♠❛tr✐③ ❞❡ ❛❞❥❛❝ê♥❝✐❛s ❡ ♦✉tr❛ s✉♣õ❡ q✉❡ ♦ ❣r❛❢♦ é ❞❛❞♦ ♣♦r ❧✐st❛s ❞❡ ❛❞❥❛❝ê♥❝✐❛✳✭❢♦♥t❡✮
✺✳ ❈❛♠✐♥❤♦ ✈❡rs✉s ❝❛♠✐♥❤♦ s✐♠♣❧❡s✳ ▼♦str❡ q✉❡ ✉♠ ❣r❛❢♦ t❡♠ ✉♠ ❝❛♠✐♥❤♦ s✐♠♣❧❡s ❝♦♠ ♦r✐❣❡♠ s ❡ tér♠✐♥♦ t s❡ ❡ s♦♠❡♥t❡ s❡ t❡♠ ✉♠ ❝❛♠✐♥❤♦ ✭♥ã♦ ♥❡❝❡ss❛r✐❛♠❡♥t❡ s✐♠♣❧❡s✮ ❝♦♠ ♦r✐❣❡♠ s ❡ tér♠✐♥♦ t✳
✻✳ ❈❛♠✐♥❤♦s ✐♥✈❡rs♦s✳ ▼♦str❡ q✉❡ ❡♠ q✉❛❧q✉❡r ❣r❛❢♦ ♥ã♦✲❞✐r✐❣✐❞♦ ♦ ✐♥✈❡rs♦ ❞❡ ✉♠ ❝❛♠✐♥❤♦ t❛♠❜é♠ é ✉♠ ❝❛♠✐♥❤♦✳ ✭❢♦♥t❡✮
❊①❡r❝í❝✐♦ ■■■
✼✳ ❱❡r✐✜❝❛ ❝✐❝❧♦✳ ❊s❝r❡✈❛ ✉♠❛ ❢✉♥çã♦ ❜♦♦❧❡❛♥❛ q✉❡ ✈❡r✐✜q✉❡ s❡ ✉♠❛ s❡q✉ê♥❝✐❛ s❡q❬✵✳✳❦❪ ❞❡ ✈ért✐❝❡s ❞❡ ✉♠ ❣r❛❢♦ é ✉♠ ❝✐❝❧♦✳ ❋❛ç❛ ❞✉❛s ✈❡rsõ❡s ❞❛ ❢✉♥çã♦✿ ✉♠❛ s✉♣õ❡ q✉❡ ♦ ❣r❛❢♦ é ❞❛❞♦ ♣♦r s✉❛ ♠❛tr✐③ ❞❡ ❛❞❥❛❝ê♥❝✐❛s ❡ ♦✉tr❛ s✉♣õ❡ q✉❡ ♦ ❣r❛❢♦ é ❞❛❞♦ ♣♦r ❧✐st❛s ❞❡ ❛❞❥❛❝ê♥❝✐❛✳ ✭❢♦♥t❡✮
✽✳ ❋❛ç❛ ✉♠❛ ❧✐st❛ ❞❡ t♦❞♦s ♦s ❝✐❝❧♦s s✐♠♣❧❡s ✭❞✐❢❡r❡♥t❡s ❡♥tr❡ s✐✮ ♥♦ ❣r❛❢♦ ❞❡✜♥✐❞♦ ♣❡❧♦s ❛r❝♦s ✵✲✺ ✺✲✹ ✼✲✽ ✹✲✸ ✵✲✷ ✾✲✶✶ ✵✲✶ ✶✶✲✶✷ ✸✲✺ ✾✲✶✷ ✾✲✶✵ ✶✵✲✾ ✻✲✹ ✵✲✻✳✭❢♦♥t❡✮
✾✳ ❋❛ç❛ ✉♠❛ ❧✐st❛ ❞❡ t♦❞♦s ♦s ❞✐❢❡r❡♥t❡s ❝✐❝❧♦s s✐♠♣❧❡s ♥♦ ❣r❛❢♦ ❞❡✜♥✐❞♦ ♣❡❧♦ ❝♦♥❥✉♥t♦ ❞❡ ❛r❝♦s ✵✲✹ ✶✲✵ ✷✲✶ ✷✲✸ ✸✲✵ ✸✲✹ ✹✲✶ ✹✲✷✳ ❋❛ç❛ ✉♠❛ ❧✐st❛ ❞❡ t♦❞♦s ♦s ❝✐❝❧♦s s✐♠♣❧❡s ♥♦ ❣r❛❢♦ ❞❡✜♥✐❞♦ ♣❡❧♦ ❝♦♥❥✉♥t♦ ❞❡ ❛r❝♦s ✵✲✷ ✶✲✵ ✷✲✶ ✷✲✸ ✸✲✵ ✸✲✶✳ ✭❢♦♥t❡✮
✶✵✳ ❋❛ç❛ ✉♠❛ ❧✐st❛ ❞❡ t♦❞♦s ♦s ❝✐❝❧♦s s✐♠♣❧❡s ♥♦ ❣r❛❢♦ ❞❡✜♥✐❞♦ ♣❡❧♦ ❝♦♥❥✉♥t♦ ❞❡ ❛r❝♦s ✵✲✷ ✶✲✵ ✷✲✶ ✷✲✸ ✸✲✵ ✸✲✶✳ ✭❢♦♥t❡✮
❊①❡r❝í❝✐♦ ■❱
✶✶✳ ❋❛ç❛ ✉♠❛ ❧✐st❛ ❞❡ t♦❞♦s ♦s ❝✐❝❧♦s s✐♠♣❧❡s ♥♦ ❣r❛❢♦ ♥ã♦✲❞✐r✐❣✐❞♦ ❞❡✜♥✐❞♦ ♣❡❧♦ ❝♦♥❥✉♥t♦ ❞❡ ❛r❡st❛s ✵✲✶ ✶✲✷ ✷✲✸✳ ✭❢♦♥t❡✮
✶✷✳ ❈✐❝❧♦s ✈❡rs✉s ❝✐❝❧♦s s✐♠♣❧❡s✳ ❙❡❥❛ ❛ ✉♠ ❛r❝♦ ❞❡ ✉♠ ❣r❛❢♦✳ ▼♦str❡ q✉❡ ❛ ♣❡rt❡♥❝❡ ❛ ✉♠ ❝✐❝❧♦ s❡ s♦♠❡♥t❡ s❡ ❛ ♣❡rt❡♥❝❡ ❛ ✉♠ ❝✐❝❧♦ s✐♠♣❧❡s✳ ✭❢♦♥t❡✮
❈♦♥❡❝t✐✈✐❞❛❞❡
• ❯♠ ❣r❛❢♦ é ❝♦♥❡①♦ s❡ ❡①✐st❡ ✉♠ ❝❛♠✐♥❤♦ ❡♥tr❡ q✉❛✐sq✉❡r ❞♦✐s ❞♦s s❡✉s ✈ért✐❝❡s✳
• H é ✉♠ ❝♦♠♣♦♥❡♥t❡ ❝♦♥❡①♦ ❞❡ G s❡✿
• H é ✉♠ s✉❜❣r❛❢♦ ❝♦♥❡①♦ ❞❡G✱
• H ♥ã♦ é s✉❜❣r❛❢♦ ❞❡ ♥❡♥❤✉♠ ❝♦♠♣♦♥❡♥t❡ ❝♦♥❡①♦ ❞❡ G✳ • ❯♠ ❣r❛❢♦ ♣♦❞❡ s❡r ♣❛rt✐❝✐♦♥❛❞♦ ❡♠ s❡✉s ❝♦♠♣♦♥❡♥t❡s ❝♦♥❡①♦s✳ • ❚♦❞♦ ✈ért✐❝❡ ✐s♦❧❛❞♦ é ✉♠ ❝♦♠♣♦♥❡♥t❡ ❝♦♥❡①♦✳ ❯♠ ✈ért✐❝❡ v é
✐s♦❧❛❞♦ s❡ deg(v) = 0✳
❉✐stâ♥❝✐❛ ❡ ❉✐â♠❡tr♦
• ❆ ❞✐stâ♥❝✐❛ ❡♥tr❡ ❞♦✐s ✈ért✐❝❡su ❡ v✱ ❞❡♥♦t❛❞❛ ♣♦r ✭✳u, v)✱ é ♦
❝♦♠♣r✐♠❡♥t♦ ❞♦ ♠❡♥♦r ❝❛♠✐♥❤♦ ❡♥tr❡ ❡st❡s ✈ért✐❝❡s✳
• ❖ ❞✐â♠❡tr♦ ❞❡ ✉♠ ❣r❛❢♦G✱ ❞❡♥♦t❛❞♦ ♣♦r ❞✐❛♠(G)✱ é ❛ ♠❛✐♦r
❞❛s ❞✐stâ♥❝✐❛s ❡♠ G✳
• ❊①❡♠♣❧♦✿ ❞✐❛♠(G) = 3,❞✐❛♠(H) = 4✳
❈♦rt❡s ❡ ❈♦♥❡①õ❡s
• ❙❡❥❛G ✉♠ ❣r❛❢♦ ❝♦♥❡①♦✳
• ❯♠ ✈ért✐❝❡v é ✉♠ ❝♦rt❡ s❡ r❡♠♦✈❡♥❞♦ ❡st❡ ✈ért✐❝❡ ♦ ❣r❛❢♦
t♦r♥❛✲s❡ ❞❡s❝♦♥❡①♦✳
• ❯♠❛ ❛r❡st❛ e é ✉♠❛ ❝♦♥❡①ã♦ s❡ r❡♠♦✈❡♥❞♦ ❡st❛ ❛r❡st❛ ♦ ❣r❛❢♦
t♦r♥❛✲s❡ ❞❡s❝♦♥❡①♦✳
• ❊①❡♠♣❧♦✿ D é ✉♠ ❝♦rt❡ ❡♠ G❀ e={D, F} é ✉♠❛ ❝♦♥❡①ã♦ ❡♠ H✳
❊①❡r❝í❝✐♦ ■
✶✳ ❋❛ç❛ ✉♠❛ ❧✐st❛ ❞❡ t♦❞♦s ♦s s✉❜❣r❛❢♦s ❝♦♥❡①♦s ❞♦ ❣r❛❢♦ ❞❡✜♥✐❞♦ ♣❡❧♦ ❝♦♥❥✉♥t♦ ❞❡ ❛r❡st❛s ✵✲✶ ✵✲✷ ✵✲✸ ✶✲✸ ✷✲✸✳ ◗✉❛✐s ❞❡ss❡s s✉❜❣r❛❢♦s sã♦ ✐♥❞✉③✐❞♦s❄ ✭❢♦♥t❡✮
✷✳ ❙❡❥❛r ✉♠ ✈ért✐❝❡ ❞❡ ✉♠ ❣r❛❢♦✳ ❙✉♣♦♥❤❛ q✉❡ t♦❞♦ ✈ért✐❝❡ v ❞♦
❣r❛❢♦ é tér♠✐♥♦ ❞❡ ✉♠ ❝❛♠✐♥❤♦ ❝♦♠ ♦r✐❣❡♠r✳ ▼♦str❡ q✉❡ ♦
❣r❛❢♦ é ❝♦♥❡①♦✳ ✭❢♦♥t❡✮
✸✳ Pr♦♣r✐❡❞❛❞❡ ❞♦ ❝♦rt❡ ✈❛③✐♦✳ Pr♦✈❡ q✉❡ ✉♠ ❣r❛❢♦ é ❞❡s❝♦♥❡①♦ s❡ ❡ s♦♠❡♥t❡ s❡ ❛❧❣✉♠ ❝♦♥❥✉♥t♦ ♥ã♦✲tr✐✈✐❛❧ ❞❡ s❡✉s ✈ért✐❝❡s é ✐s♦❧❛❞♦✳ ✭❢♦♥t❡✮
✹✳ ◆ú♠❡r♦ ❞❡ ❛r❡st❛s✳ ◗✉❛♥t❛s ❛r❡st❛s t❡♠ ✉♠ ❣r❛❢♦ ❝♦♥❡①♦ ❝♦♠ ❱ ✈ért✐❝❡s❄ ✭❢♦♥t❡✮
❊①❡r❝í❝✐♦ ■■
✺✳ ❊s❝r❡✈❛ ✉♠❛ ❢✉♥çã♦ ❯●❘❆P❍✐s❈♦♥♥❡❝t❡❞✭✮ q✉❡ ❞❡❝✐❞❛ s❡ ✉♠ ❣r❛❢♦ é ♦✉ ♥ã♦ é ❝♦♥❡①♦✳ ◆♦ ❝❛s♦ ❞❡ r❡s♣♦st❛ ♥❡❣❛t✐✈❛✱ q✉❡ ✐♥❢♦r♠❛çã♦ ❛❞✐❝✐♦♥❛❧ ❛ ❢✉♥çã♦ ♣♦❞❡r✐❛ ❞❡✈♦❧✈❡r ❝♦♠♦ ♣r♦✈❛ ❞❡ q✉❡ ❛ r❡s♣♦st❛ ❡stá ❝♦rr❡t❛❄ ✭❢♦♥t❡✮
✻✳ ❈❛♠✐♥❤♦s✳ ❊s❝r❡✈❛ ✉♠ ♣❡q✉❡♥♦ ♣r♦❣r❛♠❛ q✉❡ r❡❝❡❜❛ ✉♠ ❣r❛❢♦
G❡ ✉♠❛ ❧✐st❛ ❞❡ ♣❛r❡s ❞❡ ✈ért✐❝❡s ❡ ✐♠♣r✐♠❛✱ ♣❛r❛ ❝❛❞❛ ♣❛r
(s, t)✱ ✉♠ ❝❛♠✐♥❤♦ ❞❡ s ❛ t✳ ✭❢♦♥t❡✮
✼✳ ●r❛❢♦s ❝♦♥❡①♦s ❛❧❡❛tór✐♦s✳ ❊s❝r❡✈❛ ✉♠ ❛❧❣♦r✐t♠♦ ♣❛r❛ ❝♦♥str✉✐r ❣r❛❢♦s ❛❧❡❛tór✐♦s ❝♦♥❡①♦s ❝♦♠V ✈ért✐❝❡s ❡ E ❛r❡st❛s✳ ❖ s❡✉
❛❧❣♦r✐t♠♦ ❞❡✈❡ ♣r♦❞✉③✐r ❝♦♠ ❛ ♠❡s♠❛ ♣r♦❜❛❜✐❧✐❞❛❞❡ q✉❛❧q✉❡r ❞♦s ❣r❛❢♦s ❝♦♥❡①♦s ❝♦♠V ✈ért✐❝❡s ❡ E ❛r❡st❛s ✭❢♦♥t❡✮
❊①❡r❝í❝✐♦ ■■■
✽✳ ▼♦str❡ q✉❡ ✉♠❛ ❝♦♠♣♦♥❡♥t❡ ❝♦♥❡①❛ ❞❡ ✉♠ ❣r❛❢♦ G é ✉♠
s✉❜❣r❛❢♦ ❝♦♥❡①♦ ♠❛①✐♠❛❧ ❞❡ G✳ ❖ ❛❞❥❡t✐✈♦ ♠❛①✐♠❛❧ s✐❣♥✐✜❝❛ ♦
s❡❣✉✐♥t❡✿ s❡H é ❝♦♠♣♦♥❡♥t❡ ❝♦♥❡①❛ ❞❡ G❡♥tã♦ ♥ã♦ ❡①✐st❡ ✉♠
❣r❛❢♦ ❝♦♥❡①♦ H′ t❛❧ q✉❡H ⊂H′ ⊆G✱ ♦✉ s❡❥❛✱ ♥ã♦ ❡①✐st❡ s✉❜❣r❛❢♦ ❝♦♥❡①♦ H′ ❞❡G t❛❧ q✉❡H é s✉❜❣r❛❢♦ ♣ró♣r✐♦ ❞❡ H′✳ ✭❢♦♥t❡✮
✾✳ ❉❡t❡r♠✐♥❡ ♦ ♥ú♠❡r♦ ❞❡ ❝♦♠♣♦♥❡♥t❡s ❝♦♥❡①❛s ❞♦ ❣r❛❢♦ ♥❞ ❞❡✜♥✐❞♦ ♣❡❧♦ ❝♦♥❥✉♥t♦ ❞❡ ❛r❡st❛s ✸✲✼ ✶✲✹ ✼✲✽ ✵✲✺ ✺✲✷ ✸✲✽ ✷✲✾ ✵✲✻ ✹✲✾ ✷✲✻ ✻✲✹✳ ✭❢♦♥t❡✮
✶✵✳ ▼♦str❡ q✉❡ t♦❞❛ ❛r❡st❛ ❞❡ ✉♠ ❣r❛❢♦ t❡♠ ❛♠❜❛s ❛s ♣♦♥t❛s ♥❛ ♠❡s♠❛ ❝♦♠♣♦♥❡♥t❡ ❝♦♥❡①❛✳ ✭❢♦♥t❡✮
✶✶✳ ▼♦str❡ q✉❡ t♦❞♦ ✈ért✐❝❡ ❞❡ ✉♠ ❣r❛❢♦ ♣❡rt❡♥❝❡ ❛ ✉♠❛ ❡ ✉♠❛ só ❞❡ s✉❛s ❝♦♠♣♦♥❡♥t❡s ❝♦♥❡①❛s✳ ✭❢♦♥t❡✮
❆s ♣♦♥t❡s ❞❡ ❑ö♥✐s❜❡r❣
➱ ♣♦ssí✈❡❧ ❢❛③❡r ✉♠ ♣❛ss❡✐♦ ✈✐s✐t❛♥❞♦ ❝❛❞❛ ♣♦♥t❡ ❛♣❡♥❛s ✉♠❛ ✈❡③❄
●r❛❢♦ ❊✉❧❡r✐❛♥♦
• ❯♠ ♠✉❧t✐❣r❛❢♦ é ❞✐t♦ ❛tr❛✈❡ssá✈❡❧ s❡
• ❡①✐st❡ ✉♠ ❝❛♠✐♥❤♦ q✉❡ ✈✐s✐t❛ t♦❞♦s ♦s ✈ért✐❝❡s ❡ ❝❛❞❛ ❛r❡st❛ é ✈✐s✐t❛❞❛ ❡①❛t❛♠❡♥t❡ ✉♠❛ ✈❡③✳
• ❚❛♠❜é♠ ❝❤❛♠❛❞❛ ❞❡ tr✐❧❤❛ ❛tr❛✈❡ssá✈❡❧✳
• ❯♠ ❣r❛❢♦ só ♣♦❞❡ s❡r ❛tr❛✈❡ssá✈❡❧ s❡ s❡✉s ✈ért✐❝❡s ✐♥t❡r♠❡❞✐ár✐♦s t✐✈❡r❡♠ ❣r❛✉ ♣❛r ✭✉♠ ✈ért✐❝❡ é ✐♥t❡r♠❡❞✐ár✐♦ s❡ ♥ã♦ é ♥❡♠ ♦ ♣r✐♠❡✐r♦ ♥❡♠ ♦ ú❧t✐♠♦ ❞♦ ♣❛ss❡✐♦✮✳
• ●r❛❢♦ ❡✉❧❡r✐❛♥♦✿ ✉♠ ❣r❛❢♦ ❝♦♥❡①♦ ✜♥✐t♦ é ❡✉❧❡r✐❛♥♦ s❡ ❡ s♦♠❡♥t❡ s❡ ❝❛❞❛ ✈ért✐❝❡ t❡♠ ❣r❛✉ ♣❛r✳
• ◗✉❛❧q✉❡r ❣r❛❢♦ ❝♦♥❡①♦ ✜♥✐t♦ ❝♦♠ ❞♦✐s ✈ért✐❝❡s í♠♣❛r❡s é
❛tr❛✈❡ssá✈❡❧✳ ❯♠❛ tr✐❧❤❛ ❛tr❛✈❡ssá✈❡❧ ♣♦❞❡ ❝♦♠❡ç❛r ❡♠ q✉❛❧q✉❡r ✈ért✐❝❡ í♠♣❛r ❡ t❡r♠✐♥❛r ♥♦ ♦✉tr♦ ✈ért✐❝❡ í♠♣❛r✳
❆s ♣♦♥t❡s ❞❡ ❑ö♥✐s❜❡r❣
➱ ♣♦ssí✈❡❧ ❢❛③❡r ✉♠ ♣❛ss❡✐♦ ✈✐s✐t❛♥❞♦ ❝❛❞❛ ♣♦♥t❡ ❛♣❡♥❛s ✉♠❛ ✈❡③❄
◆➹❖✦
●r❛❢♦ ❍❛♠✐❧t♦♥✐❛♥♦
• ❈✐r❝✉✐t♦ ❤❛♠✐❧t♦♥✐❛♥♦✿ ❝❛♠✐♥❤♦ ❢❡❝❤❛❞♦ q✉❡ ✈✐s✐t❛ t♦❞♦s ♦s ✈ért✐❝❡s ❞♦ ❣r❛❢♦ ❡①❛t❛♠❡♥t❡ ✉♠❛ ✈❡③ ✭♣♦❞❡ r❡♣❡t✐r ❛r❡st❛s✮✳ ➱ ✉♠ ❝✐❝❧♦✳
• ❈✐r❝✉✐t♦ ❡✉❧❡r✐❛♥♦✿ ♣❡r❝♦rr❡ ❝❛❞❛ ❛r❡st❛ ❡①❛t❛♠❡♥t❡ ✉♠❛ ✈❡③✱ ♣♦❞❡ r❡♣❡t✐r ✈ért✐❝❡s✳
• ❯♠ ❣r❛❢♦ ❤❛♠✐❧t♦♥✐❛♥♦ ❛❞♠✐t❡ ✉♠ ❝✐❝❧♦ ❤❛♠✐❧t♦♥✐❛♥♦ ♣♦r t♦❞♦s ♦s s❡✉s ✈ért✐❝❡s✳
●r❛❢♦s r♦t✉❧❛❞♦s ❡ ♣♦♥❞❡r❛❞♦s
• ❯♠ ❣r❛❢♦ r♦t✉❧❛❞♦ ❝♦♥té♠ ❞❛❞♦s ❛ss♦❝✐❛❞♦s ❛ s❡✉s ✈ért✐❝❡s ❡✴♦✉ s✉❛s ❛r❡st❛s✳
• ❯♠ ❣r❛❢♦ ♣♦♥❞❡r❛❞♦ ❝♦♥té♠ ✉♠ ♣❡s♦ ✭♦✉ ❝♦♠♣r✐♠❡♥t♦✮ ♥ã♦ ♥❡❣❛t✐✈♦ w(e)❛ss♦❝✐❛❞♦ ❛ ❝❛❞❛ ❛r❡st❛ e✳
• ❖ ❝♦♠♣r✐♠❡♥t♦ ❞❡ ✉♠ ❝❛♠✐♥❤♦ ❡♠ ✉♠ ❣r❛❢♦ ♣♦♥❞❡r❛❞♦ é ❛ s♦♠❛ ❞♦s ♣❡s♦s ❞❛ ❛r❡st❛s ❞♦ ❝❛♠✐♥❤♦✳
• ❖ ♠❡♥♦r ❝❛♠✐♥❤♦ ❡♥tr❡ ❞♦✐s ✈ért✐❝❡ ❡♠ ✉♠ ❣r❛❢♦ ♣♦♥❞❡r❛❞♦ é ✉♠ ❝❛♠✐♥❤♦ ❝♦♠ ♦ ♠❡♥♦r ❝♦♠♣r✐♠❡♥t♦ ♣♦ssí✈❡❧✳
✭❊①✳✿P, A1, A2, A5, A3, A6, Q✮
●r❛❢♦ ❝♦♠♣❧❡t♦
• ❯♠ ❣r❛❢♦ é ❝♦♠♣❧❡t♦ s❡ ❝❛❞❛ ✈ért✐❝❡ ❡stá ❧✐❣❛❞♦ ❛ t♦❞♦s ♦s ♦✉tr♦s✳
• ❯♠ ❣r❛❢♦ ❝♦♠♣❧❡t♦ ❝♦♠n ✈ért✐❝❡s é ❞❡♥♦t❛❞♦ ♣♦rKn✳
●r❛❢♦ r❡❣✉❧❛r
• ❯♠k✲r❡❣✉❧❛r é ❛q✉❡❧❡ ♥♦ q✉❛❧ t♦❞❛s ♦s ✈ért✐❝❡s tê♠ ♦ ♠❡s♠♦
❣r❛✉ k✳
• ❯♠ ❣r❛❢♦ ✷✲r❡❣✉❧❛r ❝♦♠ n ✈ért✐❝❡s é ❝❤❛♠❛❞♦ n✲❝✐❝❧♦✳
●r❛❢♦ r❡❣✉❧❛r
• ❖ ❣r❛❢♦ ✵✲r❡❣✉❧❛r é ♦ ❣r❛❢♦ tr✐✈✐❛❧✳ • ❖ ❣r❛❢♦ ✶✲r❡❣✉❧❛r éK2✳
• Kn é ✉♠ ❣r❛❢♦ ✭n−1✮✲r❡❣✉❧❛r✳
• ❖s ❣r❛❢♦s ✸✲r❡❣✉❧❛r❡s tê♠ ✉♠ ♥ú♠❡r♦ ♣❛r ❞❡ ✈ért✐❝❡s✳ • ❊①✐st❡♠ ❛♣❡♥❛s ✶✾ ❣r❛❢♦s ✸✲r❡❣✉❧❛r❡s ❝♦♠ ✶✵ ✈ért✐❝❡s✳
●r❛❢♦s ❜✐♣❛rt✐❞♦s
• ❯♠ ❣r❛❢♦ G(V, E)é ❜✐♣❛rt✐❞♦ s❡ s❡✉ ❝♦♥❥✉♥t♦ ❞❡ ✈ért✐❝❡s V
♣♦❞❡ s❡r ♣❛rt✐❝✐♦♥❛❞♦ ❡♠ ❞♦✐s ❝♦♥❥✉♥t♦sM ❡ N ❞❡ ♠♦❞♦ q✉❡
❝❛❞❛ ❛r❡st❛ ❞❡ G ❝♦♥❡❝t❛ ✉♠ ✈ért✐❝❡ ❞❡M ❛ ♦✉tr♦ ❞❡ N✳
• ❊♠ ✉♠ ❣r❛❢♦ ❜✐♣❛rt✐❞♦ ❝♦♠♣❧❡t♦ ❝❛❞❛ ✈ért✐❝❡ ❞❡ M s❡ ❧✐❣❛ ❛
t♦❞♦s ♦s ✈ért✐❝❡s ❞❡N✳
• Km,n✱ é ♦ ❣r❛❢♦ ❜✐♣❛rt✐❞♦s ❝♦♠♣❧❡t♦ ❝♦♠ m ✈ért✐❝❡s ❡♠ M ❡ n
✈ért✐❝❡s ❡♠ N✳ P❛❞r♦♥✐③❛✲s❡m ≤n✳ Km,n t❡♠ mn ❛r❡st❛s✳
➪r✈♦r❡s
• ❯♠ ár✈♦r❡s é ✉♠ ❣r❛❢♦ ❝♦♥❡①♦ s❡♠ ❝✐❝❧♦s✳ • ❯♠❛ ✢♦r❡st❛ é ✉♠ ❣r❛❢♦ s❡♠ ❝✐❝❧♦s✳
• ❖s ❝♦♠♣♦♥❡♥t❡s ❝♦♥❡①♦s ❞❛ ✢♦r❡st❛ sã♦ ár✈♦r❡s✳
• ❯♠❛ ár✈♦r❡s ❞❡❣❡♥❡r❛❞❛ t❡♠ ✉♠ ú♥✐❝♦ ✈ért✐❝❡ ❡ ♥❡♥❤✉♠❛ ❛r❡st❛✳
❖s ❝❛♠✐♥❤♦s ♥❛s ár✈♦r❡s
❙❡❥❛T ✉♠❛ ár✈♦r❡✳
• ❊①✐st❡ ✉♠ ú♥✐❝♦ ❝❛♠✐♥❤♦ s✐♠♣❧❡s ❡♥tr❡ ❞♦✐s ✈ért✐❝❡s ❞❡ T✳
• ❙❡ ❡①✐st✐ss❡ ♠❛✐s ❞❡ ✉♠ ❝❛♠✐♥❤♦ s✐♠♣❧❡s s❡r✐❛ ♣♦ssí✈❡❧ ❢♦r♠❛r ✉♠ ❝✐❝❧♦✳
• ❙❡ ❝♦♥str✉✐r♠♦s ✉♠ ❣r❛❢♦ T′ ❛❞✐❝✐♦♥❛♥❞♦ ❛T ✉♠❛ ♥♦✈❛ ❛r❡st❛
e={u, v}✱ ✈❛✐ ❡①✐st✐r ♠❛✐s ❞❡ ✉♠ ❝❛♠✐♥❤♦ s✐♠♣❧❡s ❡♥tr❡ u ❡v✱
❧♦❣♦ T′ ♥ã♦ é ✉♠❛ ár✈♦r❡✳
• ❙❡ ❝♦♥str✉✐r♠♦s ✉♠ ❣r❛❢♦ T′′ r❡♠♦✈❡♥❞♦ ❞❡ T ❛ ❛r❡st❛
e={u, v}✱ ♥ã♦ ✈❛✐ ♠❛✐s ❡①✐st✐r ✉♠ ❝❛♠✐♥❤♦ s✐♠♣❧❡s ❡♥tr❡ u ❡ v✱
T′′ é ❞❡s❝♦♥❡①♦✱ ❧♦❣♦ ♥ã♦ é ✉♠❛ ár✈♦r❡✳ • T′′ é ✉♠❛ ✢♦r❡st❛❄
n
✈ért✐❝❡s ❡
n
−
1
❛r❡st❛s
❚♦❞❛ ár✈♦r❡ ❝♦♠ n ✈ért✐❝❡s t❡♠ ❡①❛t❛♠❡♥t❡ n−1 ❛r❡st❛s✳ Pr♦✈❛ ♣♦r ✐♥❞✉çã♦✿
• ❱❡r❞❛❞❡ ♣❛r❛ n= 1,2❡ ✸✳
• ❙✉♣♦♥❤❛ q✉❡ é ✈❡r❞❛❞❡ ♣❛r❛n < n0✳ • ❙❡❥❛T0 ✉♠❛ ár✈♦r❡ ❝♦♠ n0 ✈ért✐❝❡s✳
• ❘❡♠♦✈❛ ✉♠❛ ❛r❡st❛ ❞❡ T ❣❡r❛♥❞♦ ❞✉❛s ár✈♦r❡s T1 ❡ T2✱ ❝♦♠ n1 ❡n2 ♥ós r❡s♣❡❝t✐✈❛♠❡♥t❡✳
• T1 t❡♠ n1−1 ❛r❡st❛s ❡T2 t❡♠n2−1 ❛r❡st❛s✳
• ▲♦❣♦T0 t❡♠1 + (n1−1) + (n2−1) =n0 −1 ❛r❡st❛s✱ ❧❡♠❜r❡ q✉❡n0 =n1+n2✳
➪r✈♦r❡s ●❡r❛❞♦r❛s
• ❙❡❥❛G ✉♠ ❣r❛❢♦ ❝♦♥❡①♦✳
• ❙❡❥❛T ✉♠ s✉❜❣r❛❢♦ ❞❡ G✳
• ❙❡T é ✉♠❛ ár✈♦r❡ ❡ ✐♥❝❧✉✐ t♦❞♦s ♦s ✈ért✐❝❡s ❞❡G✱ ❡♥tã♦ T é
✉♠❛ ár✈♦r❡ ❣❡r❛❞♦r❛✳
➪r✈♦r❡ ❣❡r❛❞♦r❛ ♠í♥✐♠❛
• ❯♠❛ ár✈♦r❡ ❣❡r❛❞♦r❛ ♠í♥✐♠❛ ❡♠ ✉♠ ❣r❛❢♦ ❝♦♥❡①♦ ❝♦♠ ♣❡s♦ é ❛ ár✈♦r❡ ❣❡r❛❞♦r❛ ❝✉❥❛ s♦♠❛ ❞♦s ♣❡s♦s ❞❛s ❛r❡st❛s é ❛ ♠❡♥♦r ♣♦ssí✈❡❧✳
• ❆❧❣♦r✐t♠♦ ❞❡❧❡çã♦ ❞❡ ❛r❡st❛s ♣❛r❛ ❡♥❝♦♥tr❛r ár✈♦r❡ ❣❡r❛❞♦r❛ ♠í♥✐♠❛✿
✶✳ ❖r❞❡♥❡ ❛s ❛r❡st❛s ❞♦ ❣r❛❢♦ ❞♦ ♠❛✐♦r ♣❛r❛ ♦ ♠❡♥♦r ♣❡s♦✳
✷✳ ❙❡❣✉✐♥❞♦ ❛ ♦r❞❡♠ ❞❛s ❛r❡st❛s ❞❡❧❡t❡ ✈á ❞❡❧❡t❛♥❞♦ ❛s ❛r❡st❛s q✉❡ ♥ã♦ ❞❡s❝♦♥❡❝t❛♠ ♦ ❣r❛❢♦ ❛té q✉❡ r❡st❡♠ ❛♣❡♥❛s n−1✳
• ❆❧❣♦r✐t♠♦ ❞❡ ❑r✉s❦❛❧✿
✶✳ ❖r❞❡♥❡ ❛s ❛r❡st❛s ❞♦ ❣r❛❢♦ ❞♦ ♠❡♥♦r ♣❛r❛ ♦ ♠❛✐♦r ♣❡s♦✳
✷✳ ❆❞✐❝✐♦♥❡ ❛s ❛r❡st❛s ♥❛ ♦r❞❡♠ ❛té q✉❡ ❝♦♠♣❧❡t❡n−1 ❛r❡st❛s✱ só ❛❞✐❝✐♦♥❡ ❛q✉❡❧❛s ❛r❡st❛s q✉❡ ♥ã♦ ❣❡r❛♠ ❝✐❝❧♦s✳
• ❯♠ ú♥✐❝♦ ❣r❛❢♦ ♣♦❞❡ t❡r ✈ár✐❛s ár✈♦r❡s ❣❡r❛❞♦r❛ ♠í♥✐♠❛s ❞✐st✐♥t❛s✳
❆❧❣♦r✐t♠♦ ❞❡ ❞❡❧❡çã♦ ❞❡ ❛r❡st❛s
❆❧❣♦r✐t♠♦ ❞❡ ❑✉s❦❛❧
●r❛❢♦s ♣❧❛♥❛r❡s
• ❯♠ ❣r❛❢♦ é ♣❧❛♥❛r q✉❛♥❞♦ é ♣♦ssí✈❡❧ ❞❡s❡♥❤á✲❧♦ s❡♠ q✉❡ s✉❛s ❛r❡st❛s s❡ ❝r✉③❡♠✳
• ❚♦❞❛ ár✈♦r❡ é ♣❧❛♥❛r✳ • ❊①❡♠♣❧♦✿ ❣r❛❢♦ K4✳
▼❛♣❛s ❡ ❘❡❣✐õ❡s
• ❯♠ ♠✉❧t✐❣r❛❢♦ ♣❧❛♥❛r ♣♦❞❡ s❡r ✐♥t❡r♣r❡t❛❞♦ ❝♦♠♦ ✉♠ ♠❛♣❛ q✉❡ ❞✐✈✐❞❡ ♦ ♣❧❛♥♦ ❡♠ r❡❣✐õ❡s✳
• ❆s ❛r❡st❛s ❞❡✜♥❡♠ ❞❛s ❜♦r❞❛s ❞❡ ✉♠❛ r❡❣✐ã♦✳ • ❊st❛s ❜♦r❞❛s ♣♦❞❡♠ ♦✉ ♥ã♦ ❢♦r♠❛r ✉♠ ❝✐❝❧♦✳
• ❊①❡♠♣❧♦✿ ❛s ❜♦r❞❛s ❞❡ r3 ♥ã♦ ❢♦r❛♠ ✉♠ ❝✐❝❧♦✱ ♣♦✐s ❛ ❛r❡st❛
{E, F} s❡ r❡♣❡t❡ ♥❛ ❜♦r❞❛ (C, D, E, F, E, C).
●r❛✉ ❞❛ r❡❣✐ã♦
• ❖ ❣r❛✉ ❞❡ ✉♠❛ r❡❣✐ã♦ r✱ ❞❡♥♦t❛❞♦ ♣♦r deg(r)✱ é ♦
❝♦♠♣r✐♠❡♥t♦ ❞♦ ❝❛♠✐♥❤♦ ❞❛ ❜♦r❞❛ ❞❡ r✳
• ❚❡♦r❡♠❛ s♦❜r❡ ♦s ❣r❛✉s ❞❛s r❡❣✐õ❡s ❡ ♦ ♥ú♠❡r♦ ❞❡ ❛r❡st❛s ❞♦ ❣r❛❢♦✿ ❛ s♦♠❛ ❞♦s ❣r❛✉s ❞❛s r❡❣✐õ❡s ❞❡ ✉♠ ♠❛♣❛ é ✐❣✉❛❧ ❛ ❞✉❛s ✈❡③❡s ♦ ♥ú♠❡r♦ ❞❡ ❛r❡st❛s✳
❋ór♠✉❧❛ ❞❡ ❊✉❧❡r
• ❆ss♦❝✐❛ ♥ú♠❡r♦ ❞❡ ✈ért✐❝❡s p✱ ♦ ♥ú♠❡r♦ ❞❡ ❛r❡st❛s q ❡ ♦ ♥ú♠❡r♦
❞❡ r❡❣✐õ❡s r ❡♠ ✉♠ ❣r❛❢♦ ♣❧❛♥❛r ❝♦♥❡①♦ ✭♠❛♣❛✮✿
p−q−r = 2.
• ❊st❡ r❡s✉❧t❛❞♦ é ✈á❧✐❞♦ ♣❛r❛ ár✈♦r❡s❄ • ❊①❡♠♣❧♦ ❛❜❛✐①♦✿ p−q+r= 6−9 + 5.
●r❛✉ ♠í♥✐♠♦ ❞❡ ✉♠❛ r❡❣✐ã♦
• ❙❡❥❛G ✉♠ ♠✉❧t✐❣r❛❢♦ ❝♦♥❡①♦ ♣❧❛♥❛r ❝♦♠ ✸ ♦✉ ♠❛✐s ✈ért✐❝❡s
✭♥ã♦ éK1 ♥❡♠ K2✮✳
• ❙❡❥❛M ✉♠❛ r❡♣r❡s❡♥t❛çã♦ ♣❧❛♥❛r ❞❡ G✿ ✶✳ ❯♠❛ r❡❣✐ã♦ ❞❡ ❣r❛✉ ✶ é ✉♠ ❧❛ç♦✳
✷✳ ❯♠❛ r❡❣✐ã♦ ❞❡ ❣r❛✉ ✷ é ❝♦♠♣♦rt❛ ♣♦r ❛r❡st❛s ♠ú❧t✐♣❧❛s✳
✸✳ ❆s ❞❡♠❛✐s r❡❣✐õ❡s t❡♠ ❣r❛✉ ♠❛✐♦r ✐❣✉❛❧ ❛ ✸✳
• ❊♠ ✉♠ ❣r❛❢♦ s✐♠♣❧❡s ✭♥ã♦ é ♠✉❧t✐❣r❛❢♦✮ ❝♦♥❡①♦ ♣❧❛♥❛r✱ t♦❞❛s ❛s ❛r❡st❛s t❡♠ ❣r❛✉ ♠❛✐♦r ✐❣✉❛❧ ❛ ✸✳
◆ú♠❡r♦ ♠á①✐♠♦ ❞❡ ❛r❡st❛s ❡♠ ✉♠ ❣r❛❢♦ ♣❧❛♥❛r
❝♦♥❡①♦
❙❡❥❛G ✉♠ ❣r❛❢♦ ❝♦♥❡①♦ ♣❧❛♥❛r ❝♦♠p ✈ért✐❝❡s ❡ q ❛r❡st❛s✱ ❝♦♠ p≥3✱ t❡♠♦s✿
q ≤3p−6.
• ❆ s♦♠❛ ❞♦s ❣r❛✉s ❞❛s r❡❣✐õ❡s é ❞✉❛s ✈❡③❡s ♦ ♥ú♠❡r♦ ❞❡ ❛r❡st❛s✱ 2q✳
• ❖ ❣r❛✉ ❞❡ ❝❛❞❛ r❡❣✐ã♦ é ♥♦ ♠í♥✐♠♦ ✸✳
2q ≥3r ❧♦❣♦ r≥2q/3.
• ❙✉❜st✐t✉✐♥❞♦ ♥❛ ❢ór♠✉❧❛ ❞❡ ❊✉❧❡r✿
2 =p−q+r ≤p−q+2q
3 ♦✉ 2≤p−
q
3.
K
3,3é ♥ã♦ ♣❧❛♥❛r
• ●r❛❢♦ ❜✐♣❛rt✐❞♦ ❝♦♠♣❧❡t♦ ❝♦♠ ✸ ✈ért✐❝❡s ❡♠ ❝❛❞❛ ❧❛❞♦✳ • p= 6 ✈ért✐❝❡s ❡ q= 9 ❛r❡st❛s✳
❙❡ ❢♦ss❡ ♣❧❛♥❛r✿
• P❡❧❛ ❢ór♠✉❧❛ ❞❡ ❊✉❧❡r t❡r✐❛ ✺ r❡❣✐õ❡s✳
• ■♠♣♦ssí✈❡❧ t❡r r❡❣✐õ❡s ❞❡ ❣r❛✉ ✸ ♣♦r s❡r ❜✐♣❛rt✐❞♦✳ • ❚♦❞❛ r❡❣✐ã♦ t❡♠ ♥♦ ♠í♥✐♠♦ ❣r❛✉ ✹✳
• ❆ s♦♠❛ ❞♦ ❣r❛✉s ❞❛ r❡❣✐õ❡s é ♠❛✐♦r ✐❣✉❛❧ ❛ ✷✵✳
• ❖ ♥ú♠❡r♦ ❞❡ ❛r❡st❛ ❞❡✈❡ s❡r ♣❡❧♦ ♠❡♥♦r ✶✵✳ ✭❈♦♥tr❛❞✐çã♦✦✮
❚❡♦r❡♠❛ ❞❡ ❑✉r❛t♦✇s❦✐
K5 ♥ã♦ é ♣❧❛♥❛r✳
• K5 é ♦ ❣r❛❢♦ ❝♦♠♣❧❡t♦ ❝♦♠ p= 5 ✈ért✐❝❡s ❡ q= 10 ❛r❡st❛s✳ • ❙❡ ❢♦ss❡ ✉♠ ❣r❛❢♦ ♣❧❛♥❛r ♦ ♥ú♠❡r♦ ♠á①✐♠♦ ❞❡ ❛r❡st❛s s❡r✐❛
q ≤3p−6 = 15−6 = 9 ✭❈♦♥tr❛❞✐çã♦✦✮.
❚❡♦r❡♠❛ ❞❡ ❑✉r❛t♦✇s❦✐
❯♠ ❣r❛❢♦ é ♥ã♦ ♣❧❛♥❛r s❡ ❡ s♦♠❡♥t❡ s❡ ❝♦♥té♠ ✉♠ s✉❜❣r❛❢♦ ❤♦♠❡♦♠♦r❢♦ ❛K3,3 ♦✉ K5✳
❈♦❧♦r❛çã♦ ❞❡ ●r❛❢♦s
• ❯♠❛ ❝♦❧♦r❛çã♦ ❡♠ ✉♠ ❣r❛❢♦ é ✉♠❛ ❛tr✐❜✉✐çã♦ ❞❡ ❝♦r❡s ❛♦ s❡✉s ✈ért✐❝❡s ❞❡ ♠♦❞♦ q✉❡ ♦s ✈ért✐❝❡s ❛❞❥❛❝❡♥t❡s tê♠ ❝♦r❡s ❞✐st✐♥t❛s✳ • ❯♠ ❣r❛❢♦ é ❞✐t♦k✲❝♦❧♦rá✈❡❧ s❡ ❡①✐st❡ ✉♠❛ ❝♦❧♦r❛çã♦ q✉❡ ✉t✐❧✐③❛ k
❝♦r❡s✳
• ❖ ♥ú♠❡r♦ ❝r♦♠át✐❝♦ ❞❡ ✉♠ ❣r❛❢♦G é ♦ ♠❡♥♦r ♥ú♠❡r♦ ❝♦r❡s
♥❡❝❡ssár✐♦ ♣❛r❛ ❢❛③❡r s✉❛ ❝♦❧♦r❛çã♦✱ ❞❡♥♦t❛❞♦ ♣♦r χ(G)✳
❆❧❣♦r✐t♠♦ ❞❡ ❲❡❧❝❤✲P♦✇❡❧❧
• ❆❧❣♦r✐t♠♦ ❞❡ ❲❡❧s❤✲P♦✇❡❧❧ ♣❛r❛ ❝♦❧♦r❛çã♦ ❞❡ ❣r❛❢♦s✳ • ❙✐♠♣❧❡s ♠❛s ♥❡♠ s❡♠♣r❡ ❢♦r♥❡❝❡ ❛ ❝♦❧♦r❛çã♦ ♠í♥✐♠❛✳ ❊♥tr❛❞❛✿ ✉♠ ❣r❛❢♦ G✳
✶✳ ❖r❞❡♥❡ ♦s ✈ért✐❝❡s ❡♠ ♦r❞❡♠ ❞❡❝r❡s❝❡♥t❡ ❞♦s ❣r❛✉s✳
✷✳ ❋❛ç❛ i= 1.
✸✳ ❊♥q✉❛♥t♦ ❡①✐st✐r ✈ért✐❝❡s ♥ã♦ ❝♦❧♦r✐❞♦
✸✳✶ ❆ss♦❝✐❡ ❛ ❝♦ri❛♦ ♣ró①✐♠♦ ✈ért✐❝❡ ❞❛ ❧✐st❛ ❛✐♥❞❛ s❡♠ ❝♦r✳
✸✳✷ ❆ss♦❝✐❡ ❛ ❝♦ri❛♦ ♣ró①✐♠♦ ✈ért✐❝❡ ❞❛ ❧✐st❛ ❛✐♥❞❛ s❡♠ ❝♦r ♥ã♦ ❛❞❥❛❝❡♥t❡ ❛♦s ✈ért✐❝❡s ❝♦♠ ❝♦ri✳
✸✳✸ i+ +.
❊①❡♠♣❧♦
❊①❡♠♣❧♦
◆ã♦ é ✷✲❝♦❧♦rá✈❡❧ ♣♦rq✉❡ A1, A2 ❡ A3 ❡stã♦ ❝♦♥❡❝t❛❞♦s ❡♥tr❡ s✐✳
❈♦❧♦r❛çõ❡s ♠á①✐♠❛✳
• χ(Kn) =n✳
• ➱ ❡q✉✐✈❛❧❡♥t❡ ❞✐③❡r s♦❜r❡ ✉♠ ❣r❛❢♦G✿
• Gé ✷✲❝♦❧♦rá✈❡❧✳ • Gé ❜✐♣❛rt✐❞♦✳
• ❚♦❞♦ ❝✐❝❧♦ ❞❡Gt❡♠ ❣r❛✉ í♠♣❛r✳ • ◗✉❛❧q✉❡r ❣r❛❢♦ ♣❧❛♥❛r é ✺✲❝♦❧♦rá✈❡❧✳ • ◗✉❛❧q✉❡r ❣r❛❢♦ ♣❧❛♥❛r é ✹✲❝♦❧♦rá✈❡❧ ✭❄✮✳
▼❛♣❛ ❞✉❛❧
• ❯t✐❧✐③❛❞♦ ♣❛r❛ ❞❡✜♥✐r ❛ ❝♦❧♦r❛çã♦ ❞❛s r❡❣✐õ❡s ❞❡ ✉♠ ♠❛♣❛✳ • ❈❛❞❛ r❡❣✐ã♦ é ✉♠ ♠❛♣❛M é r❡♣r❡s❡♥t❛❞❛ ♣♦r ✉♠ ✈ért✐❝❡ ♥♦
♠❛♣❛ ❞✉❛❧ M∗✳
• ❈❛❞❛ ❛r❡st❛ ❡♠M∗ ❝r✉③❛♠ ❛s ❛r❡st❛s q✉❡ ❢❛③❡♠ ❢r♦♥t❡✐r❛s ❡♠ M ❝♦♥❡❝t❛♥❞♦ ❞✉❛s r❡❣✐õ❡s✳
❚❡♦r❡♠❛ ❞❛s q✉❛tr♦ ❝♦r❡s
• ❆♣♣❡❧ ✫ ❑❛❦❡♥♥ ✭✶✾✼✻✮✳
• ❚♦❞♦ ❣r❛❢♦ ♣❧❛♥❛r é ✹✲❝♦❧♦rá✈❡❧✳
• ❙❡ ❛s r❡❣✐õ❡s ❞❡ q✉❛❧q✉❡r ♠❛♣❛ M sã♦ ❝♦❧♦r✐❞❛s ❞❡ ❢♦r♠❛ q✉❡
r❡❣✐õ❡s ✈✐③✐♥❤❛s tê♠ ❝♦r❡s ❞✐st✐♥t❛s✱ ❡♥tã♦ ♥ã♦ ♠❛✐s q✉❡ q✉❛tr♦ ❝♦r❡s sã♦ ♥❡❝❡ssár✐❛s✳
• ❆ ♣r♦✈❛ ❞❡st❡ t❡♦r❡♠❛ ❞❡♣❡♥❞❡✉ ❞♦ ❛✉①í❧✐♦ ❞❡ ❝♦♠♣✉t❛❞♦r❡s ♣❛r❛ ♠♦str❛r q✉❡ ♥ã♦ ❡①✐st✐❛ ✉♠ ❝♦♥tr❛✲❡①❡♠♣❧♦ ❡♠ ✉♠ ❝♦♥❥✉♥t♦ ❝❛❧❝✉❧❛❞♦ ❞❡ ❛♣r♦①✐♠❛❞❛♠❡♥t❡ ✷✵✵✵ ❣r❛❢♦s ♣❧❛♥❛r❡s✳
❘❡♣r❡s❡♥t❛çã♦ ❞❡ ●r❛❢♦s
• p✈ért✐❝❡s ❡ q ❛r❡st❛s✳
• ▼❛tr✐③ ❞❡ ❛❞❥❛❝ê♥❝✐❛✳
• ❯t✐❧✐③❛❞❛ ♣❛r❛ ❣r❛❢♦s ❞❡♥s♦s✳ • ▲✐st❛ ❞❡ ❛❞❥❛❝ê♥❝✐❛✳
• ❯t✐❧✐③❛❞❛ ♣❛r❛ ❣r❛❢♦s ❡s♣❛rs♦s✳ • ▼❛tr✐③ ❞❡ ✐♥❝✐❞ê♥❝✐❛✳
• ❈❛❞❛ r❡♣r❡s❡♥t❛çã♦ é ♠❛✐s ❛❞❡q✉❛❞❛ ❛ ✉♠ ❛❧❣♦r✐t♠♦✳
• ➱ ❝♦♠✉♠ ❝♦♠♣❛rt✐❧❤❛r ❣r❛❢♦s ❝♦♠♦ ❛rq✉✐✈♦s ❞❡ ❧✐st❛s ❞❡ ❛r❡st❛s✱ ♥♦ q✉❛❧ ❝❛❞❛ ❧✐♥❤❛ t❡♠ ✷ ♦✉ ✸ ❡❧❡♠❡♥t♦s✿ ❝❛❞❛ ✈ért✐❝❡ ✭❡ ♦ ♣❡s♦✮✳
▼❛tr✐③ ❞❡ ❛❞❥❛❝ê♥❝✐❛
• ❘❡❧❛❝✐♦♥❛ ❝❛❞❛ ✈ért✐❝❡ ❝♦♠ t♦❞♦s ♦s ✈ért✐❝❡s ❞♦ ❣r❛❢♦✳ • ❖ ✈❛❧♦r❡s ❞❛ ♠❛tr✐③ ♣♦❞❡♠ r❡♣r❡s❡♥t❛r✿
• ❆ ❡①✐stê♥❝✐❛ ❞❡ ❛r❡st❛s ❡♠ ✉♠ ❣r❛❢♦ s✐♠♣❧❡s✳ • ❖ ♣❡s♦ ❡♠ ✉♠ ❣r❛❢♦ ♣♦♥❞❡r❛❞♦✳
• ❖ ♥ú♠❡r♦ ❞❡ ❛r❡st❛s ❡♠ ✉♠ ♠✉❧t✐❣r❛❢♦✳
▲✐st❛ ❞❡ ❛❞❥❛❝ê♥❝✐❛
• ❚❡♠ ✉♠❛ ❧✐st❛ ♣❛r❛ ❝❛❞❛ ✈ért✐❝❡✳
• ❆ ❧✐st❛ ✐♥❞✐❝❛ ❛ q✉❛✐s ✈ért✐❝❡s ❡stá ❧✐❣❛❞♦ ♦ ✈ért✐❝❡ ✏❞♦♥♦✑ ❞❡st❛ ❧✐st❛✳
▼❛tr✐③ ❞❡ ✐♥❝✐❞ê♥❝✐❛
• ❘❡❧❛❝✐♦♥❛ ❛r❡st❛s ❡ ✈ért✐❝❡s✳
• ▼❛r❝❛ ✶ q✉❛♥❞♦ ❛ ❛r❡st❛ ❡ ♦ ✈ért✐❝❡ ✐♥❝✐❞❡♠✳
❘❡❢❡rê♥❝✐❛
✶✳ ❙✳ ▲✐♣s❝❤✉t③ ✫ ▼✳ ▲✳ ▲✐♣s♦♥✳ ❚❡♦r✐❛ ❡ Pr♦❜❧❡♠❛s ❞❡ ▼❛t❡♠át✐❝❛ ❉✐s❝r❡t❛ ✷❛ ❡❞✐çã♦✳ ❊❞✐t♦r❛ ❇♦♦❦♠❛♥ ✭❈♦❧❡çã♦ ❙❝❤❛✉♠✮✱ ✷✵✵✹✳
✷✳ ❁❤tt♣✿✴✴❝✐♦✳❝♦♠✳❜r✴ ❢❛❝❛✲❛✲t❡♦r✐❛✲❞♦s✲❣r❛❢♦s✲tr❛❜❛❧❤❛r✲♣❛r❛✲s✉❛✲❡♠♣r❡s❛✴❃ ✸✳ ❁❤tt♣s✿✴✴✇✇✇✳✐♠❡✳✉s♣✳❜r✴⑦♣❢✴❛❧❣♦r✐t♠♦s❴♣❛r❛❴❣r❛❢♦s✴❃ ✹✳ ❁❤tt♣s✿✴✴✇✇✇✳❤❡✐❞❡❧❜❡r❣✲❧❛✉r❡❛t❡✲❢♦r✉♠✳♦r❣✴❜❧♦❣✴ t❤❡✲❜r✐❞❣❡s✲♦❢✲❦♦♥✐❣s❜❡r❣✴❃ ✺✳ ❁❤tt♣✿✴✴❝♦♠♣❛❧❣✳✐♥❢✳❡❧t❡✳❤✉✴⑦t♦♥②✴❖❦t❛t❛s✴❚❉❑✴❋■◆❆▲✴ ❈❤❛♣✪✷✵✹✳P❉❋❃ ✻✳ ❁❤tt♣s✿✴✴✇✇✇✳✐❝✳✉♥✐❝❛♠♣✳❜r✴⑦❛t✐❧✐♦✴s❧✐❞❡s❲t✐s❝✳♣❞❢❃ ✼✳ ❁❤tt♣✿✴✴✇✇✇✳✐❜✐❧❝❡✳✉♥❡s♣✳❜r✴❍♦♠❡✴❉❡♣❛rt❛♠❡♥t♦s✴ ▼❛t❡♠❛t✐❝❛❆♣❧✐❝❛❞❛✴s♦❝♦rr♦✹✵✷✾✴r❡♣r❡s❡♥t❛❴❣r❛❢♦s✷✳♣❞❢❃