posets of copies embedding monoids and interpretability
play

POSETS OF COPIES, EMBEDDING MONOIDS, AND INTERPRETABILITY OF - PowerPoint PPT Presentation

POSETS OF COPIES, EMBEDDING MONOIDS, AND INTERPRETABILITY OF RELATIONAL STRUCTURES Milo s Kurili c Department of Mathematics and Informatics, University of Novi Sad, Serbia August 21, 2014 (SETTOP 2014) August 21, 2014 1 / 19 Posets


  1. Posets of copies of structures Countable binary structures [3] ro sq � P ( X ) , ⊂� i s Borel / M ro P ( ω ) / Fin 2 i s o m o r p h i c t o ♣ ♣ ♣ ♣ ♣ u n d e r CH i ♣ ♣ ♣ ♣ n F d i [ ω ] ω i i n D 5 v d e i ♣ ♣ s a t a n i l o C 4 D 4 b l c l l w e h ♣ ♣ e r e A 3 B 3 C 3 D 3 n d i o d ♣ v e t n i ℵ 0 s i s A 2 B 2 e i d e b ♣ l a i G Z e n 1 l A 1 [ ω ] ω ♣ ♣ ♣ ♣ | P ( X ) | I X P ( X ) σ - c l o s e d X a t o m l e s s sq � P ( X ) , ⊂� ♣ ♣ ♣ ℵ 0 > ℵ 0 1 | sq � P ( X ) , ⊂�| ♣ ♣ ♣ ♣ a t o m i c a t o m l e s s � P ( X ) , ⊂� ♣ ♣ ♣ (SETTOP 2014) August 21, 2014 5 / 19

  2. Posets of copies of structures Countable binary structures [3] ro sq � P ( X ) , ⊂� i s Borel / M ro P ( ω ) / Fin 2 i s o m o r p h i c t o ♣ ♣ ♣ ♣ ♣ u n d e r CH i ♣ ♣ ♣ ♣ n F d i [ ω ] ω i i n D 5 v d e i ♣ ♣ s a t a n i l o C 4 D 4 b l c l l w e h ♣ ♣ e r e A 3 B 3 C 3 D 3 n d i o d ♣ v e t G ω n i ℵ 0 s i s A 2 B 2 e i d e b ♣ l a i G Z e n 1 l A 1 [ ω ] ω ♣ ♣ ♣ ♣ | P ( X ) | I X P ( X ) σ - c l o s e d X a t o m l e s s sq � P ( X ) , ⊂� ♣ ♣ ♣ ℵ 0 > ℵ 0 1 | sq � P ( X ) , ⊂�| ♣ ♣ ♣ ♣ a t o m i c a t o m l e s s � P ( X ) , ⊂� ♣ ♣ ♣ (SETTOP 2014) August 21, 2014 5 / 19

  3. Posets of copies of structures Countable binary structures [3] ro sq � P ( X ) , ⊂� i s Borel / M ro P ( ω ) / Fin 2 i s o m o r p h i c t o ♣ ♣ ♣ ♣ ♣ u n d e r CH i ♣ ♣ ♣ ♣ n F d i [ ω ] ω i i n D 5 v d e i ♣ ♣ s a t a n i l o C 4 D 4 b l c l l w e h ♣ ♣ e r e A 3 B 3 C 3 D 3 n d i o d ♣ v e D <ω 2 t G ω n i ℵ 0 s i s A 2 B 2 e i d e b ♣ l a i G Z e n 1 l A 1 [ ω ] ω ♣ ♣ ♣ ♣ | P ( X ) | I X P ( X ) σ - c l o s e d X a t o m l e s s sq � P ( X ) , ⊂� ♣ ♣ ♣ ℵ 0 > ℵ 0 1 | sq � P ( X ) , ⊂�| ♣ ♣ ♣ ♣ a t o m i c a t o m l e s s � P ( X ) , ⊂� ♣ ♣ ♣ (SETTOP 2014) August 21, 2014 5 / 19

  4. Posets of copies of structures Countable binary structures [3] ro sq � P ( X ) , ⊂� i s Borel / M ro P ( ω ) / Fin 2 i s o m o r p h i c t o ♣ ♣ ♣ ♣ ♣ u n d e r CH i ♣ ♣ ♣ ♣ n � ω, < � F d i [ ω ] ω i i n D 5 v d e i ♣ ♣ s a t a n i l o C 4 D 4 b l c l l w e h ♣ ♣ e r e A 3 B 3 C 3 D 3 n d i o d ♣ v e D <ω 2 t G ω n i ℵ 0 s i s A 2 B 2 e i d e b ♣ l a i G Z e n 1 l A 1 [ ω ] ω ♣ ♣ ♣ ♣ | P ( X ) | I X P ( X ) σ - c l o s e d X a t o m l e s s sq � P ( X ) , ⊂� ♣ ♣ ♣ ℵ 0 > ℵ 0 1 | sq � P ( X ) , ⊂�| ♣ ♣ ♣ ♣ a t o m i c a t o m l e s s � P ( X ) , ⊂� ♣ ♣ ♣ (SETTOP 2014) August 21, 2014 5 / 19

  5. Posets of copies of structures Countable binary structures [3] ro sq � P ( X ) , ⊂� i s Borel / M ro P ( ω ) / Fin 2 i s o m o r p h i c t o ♣ ♣ ♣ ♣ ♣ u n d e r CH i ♣ ♣ ♣ ♣ n � ω, < � F d i [ ω ] ω i i n D 5 v d e i ♣ ♣ s a t Q a n i l o C 4 D 4 b l c l l w e h ♣ ♣ e r e A 3 B 3 C 3 D 3 n d i o d ♣ v e D <ω 2 t G ω n i ℵ 0 s i s A 2 B 2 e i d e b ♣ l a i G Z e n 1 l A 1 [ ω ] ω ♣ ♣ ♣ ♣ | P ( X ) | I X P ( X ) σ - c l o s e d X a t o m l e s s sq � P ( X ) , ⊂� ♣ ♣ ♣ ℵ 0 > ℵ 0 1 | sq � P ( X ) , ⊂�| ♣ ♣ ♣ ♣ a t o m i c a t o m l e s s � P ( X ) , ⊂� ♣ ♣ ♣ (SETTOP 2014) August 21, 2014 5 / 19

  6. Posets of copies of structures Countable binary structures [3] ro sq � P ( X ) , ⊂� i s Borel / M ro P ( ω ) / Fin 2 i s o m o r p h i c t o ♣ ♣ ♣ ♣ ♣ u n d e r CH i ♣ ♣ ♣ ♣ n � ω, < � F d i [ ω ] ω i i n D 5 v d e i ♣ ♣ s a t Q a n i l o C 4 D 4 b l c l l w e h ♣ ♣ e X Col ( ω, c ) r e A 3 B 3 C 3 D 3 n d i o d ♣ v e D <ω 2 t G ω n i ℵ 0 s i s A 2 B 2 e i d e b ♣ l a i G Z e n 1 l A 1 [ ω ] ω ♣ ♣ ♣ ♣ | P ( X ) | I X P ( X ) σ - c l o s e d X a t o m l e s s sq � P ( X ) , ⊂� ♣ ♣ ♣ ℵ 0 > ℵ 0 1 | sq � P ( X ) , ⊂�| ♣ ♣ ♣ ♣ a t o m i c a t o m l e s s � P ( X ) , ⊂� ♣ ♣ ♣ (SETTOP 2014) August 21, 2014 5 / 19

  7. Posets of copies of structures The hierarchy of similarities between relational structures (SETTOP 2014) August 21, 2014 6 / 19

  8. Posets of copies of structures The hierarchy of similarities between relational structures q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  9. Posets of copies of structures The hierarchy of similarities between relational structures ✟✟✟✟✟✟ X ∼ = Y q q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  10. Posets of copies of structures The hierarchy of similarities between relational structures ✟✟✟✟✟✟ X ⇆ Y q ✟✟✟✟✟✟ X ∼ = Y q q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  11. Posets of copies of structures The hierarchy of similarities between relational structures ✟✟✟✟✟✟ X ⇆ Y q P ( X ) = P ( Y ) q ✟✟✟✟✟✟ X ∼ = Y q q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  12. Posets of copies of structures The hierarchy of similarities between relational structures ✟✟✟✟✟✟ X ⇆ Y q ✟✟✟✟✟✟ P ( X ) ∼ = P ( Y ) q P ( X ) = P ( Y ) q ✟✟✟✟✟✟ X ∼ = Y q q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  13. Posets of copies of structures The hierarchy of similarities between relational structures ✟✟✟✟✟✟ X ⇆ Y sq P ( X ) ∼ = sq P ( Y ) q q ✟✟✟✟✟✟ P ( X ) ∼ = P ( Y ) q P ( X ) = P ( Y ) q ✟✟✟✟✟✟ X ∼ = Y q q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  14. Posets of copies of structures The hierarchy of similarities between relational structures ro sq P ( X ) ∼ = ro sq P ( Y ) ✟✟✟✟✟✟ q ✟✟✟✟✟✟ X ⇆ Y sq P ( X ) ∼ = sq P ( Y ) q q ✟✟✟✟✟✟ P ( X ) ∼ = P ( Y ) q P ( X ) = P ( Y ) q ✟✟✟✟✟✟ X ∼ = Y q q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  15. Posets of copies of structures The hierarchy of similarities between relational structures ro sq P ( X ) ∼ = ro sq P ( Y ) ✟✟✟✟✟✟ q ✟✟✟✟✟✟ X ⇆ Y sq P ( X ) ∼ = sq P ( Y ) q q ✟✟✟✟✟✟ P ( X ) ∼ = P ( Y ) q ❍ P ( X ) = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ∼ = Y q q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  16. Posets of copies of structures The hierarchy of similarities between relational structures ro sq P ( X ) ∼ = ro sq P ( Y ) ✟✟✟✟✟✟ q ✟✟✟✟✟✟ X ⇆ Y sq P ( X ) ∼ = sq P ( Y ) q q ✟✟✟✟✟✟ P ( X ) ∼ ❍ = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ❍ P ( X ) = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ∼ = Y q q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  17. Posets of copies of structures The hierarchy of similarities between relational structures ro sq P ( X ) ∼ = ro sq P ( Y ) ✟✟✟✟✟✟ ❍ q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ⇆ Y sq P ( X ) ∼ = sq P ( Y ) q q ✟✟✟✟✟✟ P ( X ) ∼ ❍ = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ❍ P ( X ) = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ∼ = Y q q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  18. Posets of copies of structures The hierarchy of similarities between relational structures ro sq P ( X ) ∼ = ro sq P ( Y ) ⇔ P ( X ) ≡ P ( Y ) ✟✟✟✟✟✟ ❍ q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ⇆ Y sq P ( X ) ∼ = sq P ( Y ) q q ✟✟✟✟✟✟ P ( X ) ∼ ❍ = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ❍ P ( X ) = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ∼ = Y q q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  19. Posets of copies of structures The hierarchy of similarities between relational structures ro sq P ( X ) ∼ = ro sq P ( Y ) ⇔ P ( X ) ≡ P ( Y ) ✟✟✟✟✟✟ ❍ q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ⇆ Y sq P ( X ) ∼ = sq P ( Y ) q q ✟✟✟✟✟✟ P ( X ) ∼ ❍ = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ❍ P ( X ) = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ∼ = Y q q P ( X ) = P ( Y ) ∧ X ∼ = Y q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  20. Posets of copies of structures The hierarchy of similarities between relational structures ro sq P ( X ) ∼ = ro sq P ( Y ) ⇔ P ( X ) ≡ P ( Y ) ✟✟✟✟✟✟ ❍ q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ⇆ Y sq P ( X ) ∼ = sq P ( Y ) q q ✟✟✟✟✟✟ P ( X ) ∼ ❍ = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ P ( X ) = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ∼ P ( X ) = P ( Y ) ∧ X ⇆ Y = Y q q q P ( X ) = P ( Y ) ∧ X ∼ = Y q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  21. Posets of copies of structures The hierarchy of similarities between relational structures ro sq P ( X ) ∼ = ro sq P ( Y ) ⇔ P ( X ) ≡ P ( Y ) ✟✟✟✟✟✟ ❍ q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ⇆ Y sq P ( X ) ∼ = sq P ( Y ) q q ✟✟✟✟✟✟ P ( X ) ∼ ❍ = P ( Y ) q ❍ ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ q P ( X ) ∼ P ( X ) = P ( Y ) = P ( Y ) ∧ X ⇆ Y q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ∼ P ( X ) = P ( Y ) ∧ X ⇆ Y = Y q q q P ( X ) = P ( Y ) ∧ X ∼ = Y q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  22. Posets of copies of structures The hierarchy of similarities between relational structures ro sq P ( X ) ∼ = ro sq P ( Y ) ⇔ P ( X ) ≡ P ( Y ) ✟✟✟✟✟✟ ❍ q ❍ ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ⇆ Y sq P ( X ) ∼ = sq P ( Y ) q q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ P ( X ) ∼ ❍ sq P ( X ) ∼ = P ( Y ) = sq P ( Y ) ∧ X ⇆ Y q ❍ q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ q P ( X ) ∼ P ( X ) = P ( Y ) = P ( Y ) ∧ X ⇆ Y q ❍ ❍ ❍ ❍ ❍ ✟✟✟✟✟✟ X ∼ P ( X ) = P ( Y ) ∧ X ⇆ Y = Y q q q P ( X ) = P ( Y ) ∧ X ∼ = Y q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  23. Posets of copies of structures The hierarchy of similarities between relational structures ro sq P ( X ) ∼ = ro sq P ( Y ) ⇔ P ( X ) ≡ P ( Y ) ✟✟✟✟✟✟ ❍ q ❍ ❍ ❍ m n ❍ ❍ ❍ ✟✟✟✟✟✟ X ⇆ Y sq P ( X ) ∼ = sq P ( Y ) q q ❍ ❍ ❍ j k l ❍ ❍ ✟✟✟✟✟✟ P ( X ) ∼ ❍ sq P ( X ) ∼ = P ( Y ) = sq P ( Y ) ∧ X ⇆ Y q ❍ q ❍ ❍ g h ❍ i ❍ ❍ ✟✟✟✟✟✟ q P ( X ) ∼ P ( X ) = P ( Y ) = P ( Y ) ∧ X ⇆ Y q ❍ ❍ ❍ d e f ❍ ❍ ✟✟✟✟✟✟ X ∼ P ( X ) = P ( Y ) ∧ X ⇆ Y = Y q q c b q P ( X ) = P ( Y ) ∧ X ∼ = Y a q X = Y (SETTOP 2014) August 21, 2014 6 / 19

  24. Posets of copies of structures Example: Countable scattered l. o.’ s are in Column D (SETTOP 2014) August 21, 2014 7 / 19

  25. Posets of copies of structures Example: Countable scattered l. o.’ s are in Column D Theorem ([5]) For each countable scattered linear order X • The poset sq � P ( X ) , ⊂� is atomless and σ -closed (SETTOP 2014) August 21, 2014 7 / 19

  26. Posets of copies of structures Example: Countable scattered l. o.’ s are in Column D Theorem ([5]) For each countable scattered linear order X • The poset sq � P ( X ) , ⊂� is atomless and σ -closed • Under CH we have � P ( X ) , ⊂� ≡ ( P ( ω ) / Fin ) + . (SETTOP 2014) August 21, 2014 7 / 19

  27. Posets of copies of structures Sub-example: Countable ordinals (SETTOP 2014) August 21, 2014 8 / 19

  28. Posets of copies of structures Sub-example: Countable ordinals Theorem ([6]) If α = ω γ n + r n s n + · · · + ω γ 0 + r 0 s 0 + k is a countably infinite ordinal presented in the Cantor normal form, then (SETTOP 2014) August 21, 2014 8 / 19

  29. Posets of copies of structures Sub-example: Countable ordinals Theorem ([6]) If α = ω γ n + r n s n + · · · + ω γ 0 + r 0 s 0 + k is a countably infinite ordinal presented in the Cantor normal form, then n � + � s i �� sq � P ( α ) , ⊂� ∼ � rp r i ( P ( ω γ i ) / I ω γ i ) = i = 0 (SETTOP 2014) August 21, 2014 8 / 19

  30. Posets of copies of structures Sub-example: Countable ordinals Theorem ([6]) If α = ω γ n + r n s n + · · · + ω γ 0 + r 0 s 0 + k is a countably infinite ordinal presented in the Cantor normal form, then n � + � s i �� sq � P ( α ) , ⊂� ∼ � rp r i ( P ( ω γ i ) / I ω γ i ) = i = 0 � ( P ( ω ) / Fin ) + if α < ω + ω � P ( α ) , ⊂� ≡ (SETTOP 2014) August 21, 2014 8 / 19

  31. Posets of copies of structures Sub-example: Countable ordinals Theorem ([6]) If α = ω γ n + r n s n + · · · + ω γ 0 + r 0 s 0 + k is a countably infinite ordinal presented in the Cantor normal form, then n � + � s i �� sq � P ( α ) , ⊂� ∼ � rp r i ( P ( ω γ i ) / I ω γ i ) = i = 0 � ( P ( ω ) / Fin ) + if α < ω + ω � P ( α ) , ⊂� ≡ ( P ( ω ) / Fin ) + ∗ π if α ≥ ω + ω where [ ω ] � “ π is an ω 1 -closed, separative atomless forcing”. (SETTOP 2014) August 21, 2014 8 / 19

  32. Posets of copies of structures Example: Countable non-scattered l. o.’s are in Column C (SETTOP 2014) August 21, 2014 9 / 19

  33. Posets of copies of structures Example: Countable non-scattered l. o.’s are in Column C Theorem (with S. Todorˇ cevi´ c, [10]) For each countable non-scattered linear order X we have � P ( X ) , ⊂� ≡ S ∗ π where (SETTOP 2014) August 21, 2014 9 / 19

  34. Posets of copies of structures Example: Countable non-scattered l. o.’s are in Column C Theorem (with S. Todorˇ cevi´ c, [10]) For each countable non-scattered linear order X we have � P ( X ) , ⊂� ≡ S ∗ π where • S is the Sacks forcing (SETTOP 2014) August 21, 2014 9 / 19

  35. Posets of copies of structures Example: Countable non-scattered l. o.’s are in Column C Theorem (with S. Todorˇ cevi´ c, [10]) For each countable non-scattered linear order X we have � P ( X ) , ⊂� ≡ S ∗ π where • S is the Sacks forcing • π codes a σ -closed forcing (SETTOP 2014) August 21, 2014 9 / 19

  36. Posets of copies of structures Example: Countable non-scattered l. o.’s are in Column C Theorem (with S. Todorˇ cevi´ c, [10]) For each countable non-scattered linear order X we have � P ( X ) , ⊂� ≡ S ∗ π where • S is the Sacks forcing • π codes a σ -closed forcing • 1 S � π ≡ ( P ( ω ) / Fin ) + , under CH or PFA. (SETTOP 2014) August 21, 2014 9 / 19

  37. Posets of copies of structures Countable linear orders in the A 1 − D 5 diagram scattered l. o.’s ω D 5 non-scatt. l. o.’s Q ω · ω C 4 D 4 ω + ω D 3 (SETTOP 2014) August 21, 2014 10 / 19

  38. The monoid of self-embeddings The poset P ( X ) and the monoid E mb ( X ) (SETTOP 2014) August 21, 2014 11 / 19

  39. The monoid of self-embeddings The poset P ( X ) and the monoid E mb ( X ) If M = � M , · , e � is a monoid (a semigroup with unity), the right Green’s preorder on M is defined by (SETTOP 2014) August 21, 2014 11 / 19

  40. The monoid of self-embeddings The poset P ( X ) and the monoid E mb ( X ) If M = � M , · , e � is a monoid (a semigroup with unity), the right Green’s preorder on M is defined by x � R y ⇔ ∃ z ∈ M xz = y (SETTOP 2014) August 21, 2014 11 / 19

  41. The monoid of self-embeddings The poset P ( X ) and the monoid E mb ( X ) If M = � M , · , e � is a monoid (a semigroup with unity), the right Green’s preorder on M is defined by x � R y ⇔ ∃ z ∈ M xz = y Fact If X is a relational structure and E mb ( X ) = � Emb ( X ) , ◦ , id X � the corresponding monoid of self-embeddings of X , then (SETTOP 2014) August 21, 2014 11 / 19

  42. The monoid of self-embeddings The poset P ( X ) and the monoid E mb ( X ) If M = � M , · , e � is a monoid (a semigroup with unity), the right Green’s preorder on M is defined by x � R y ⇔ ∃ z ∈ M xz = y Fact If X is a relational structure and E mb ( X ) = � Emb ( X ) , ◦ , id X � the corresponding monoid of self-embeddings of X , then • P ( X ) = { f [ X ] : f ∈ Emb ( X ) } (SETTOP 2014) August 21, 2014 11 / 19

  43. The monoid of self-embeddings The poset P ( X ) and the monoid E mb ( X ) If M = � M , · , e � is a monoid (a semigroup with unity), the right Green’s preorder on M is defined by x � R y ⇔ ∃ z ∈ M xz = y Fact If X is a relational structure and E mb ( X ) = � Emb ( X ) , ◦ , id X � the corresponding monoid of self-embeddings of X , then • P ( X ) = { f [ X ] : f ∈ Emb ( X ) } • � P ( X ) , ⊂� ∼ = asq � Emb ( X ) , ( � R ) − 1 � (SETTOP 2014) August 21, 2014 11 / 19

  44. The monoid of self-embeddings The poset P ( X ) and the monoid E mb ( X ) If M = � M , · , e � is a monoid (a semigroup with unity), the right Green’s preorder on M is defined by x � R y ⇔ ∃ z ∈ M xz = y Fact If X is a relational structure and E mb ( X ) = � Emb ( X ) , ◦ , id X � the corresponding monoid of self-embeddings of X , then • P ( X ) = { f [ X ] : f ∈ Emb ( X ) } • � P ( X ) , ⊂� ∼ = asq � Emb ( X ) , ( � R ) − 1 � • { f ∈ Emb ( X ) : f is invertible } = { f ∈ Emb ( X ) : f is regular } = Aut ( X ) (SETTOP 2014) August 21, 2014 11 / 19

  45. The monoid of self-embeddings The poset P ( X ) and the monoid E mb ( X ) If M = � M , · , e � is a monoid (a semigroup with unity), the right Green’s preorder on M is defined by x � R y ⇔ ∃ z ∈ M xz = y Fact If X is a relational structure and E mb ( X ) = � Emb ( X ) , ◦ , id X � the corresponding monoid of self-embeddings of X , then • P ( X ) = { f [ X ] : f ∈ Emb ( X ) } • � P ( X ) , ⊂� ∼ = asq � Emb ( X ) , ( � R ) − 1 � • { f ∈ Emb ( X ) : f is invertible } = { f ∈ Emb ( X ) : f is regular } = Aut ( X ) • { id X } = { f ∈ Emb ( X ) : f is idempotent } . (SETTOP 2014) August 21, 2014 11 / 19

  46. The monoid of self-embeddings The poset P ( X ) and the monoid E mb ( X ) If M = � M , · , e � is a monoid (a semigroup with unity), the right Green’s preorder on M is defined by x � R y ⇔ ∃ z ∈ M xz = y Fact If X is a relational structure and E mb ( X ) = � Emb ( X ) , ◦ , id X � the corresponding monoid of self-embeddings of X , then • P ( X ) = { f [ X ] : f ∈ Emb ( X ) } • � P ( X ) , ⊂� ∼ = asq � Emb ( X ) , ( � R ) − 1 � • { f ∈ Emb ( X ) : f is invertible } = { f ∈ Emb ( X ) : f is regular } = Aut ( X ) • { id X } = { f ∈ Emb ( X ) : f is idempotent } . Theorem If X and Y are relational structures, then X ∼ = Y ⇒ E mb ( X ) ∼ = E mb ( Y ) ⇒ � P ( X ) , ⊂� ∼ = � P ( Y ) , ⊂� (SETTOP 2014) August 21, 2014 11 / 19

  47. The monoid of self-embeddings An application of E mb ( X ) ∼ = E mb ( Y ) ⇒ � P ( X ) , ⊂� ∼ = � P ( Y ) , ⊂� (SETTOP 2014) August 21, 2014 12 / 19

  48. The monoid of self-embeddings An application of E mb ( X ) ∼ = E mb ( Y ) ⇒ � P ( X ) , ⊂� ∼ = � P ( Y ) , ⊂� Since P (( 0 , 1 ) Q , < ) �∼ = P ([ 0 , 1 ] Q , < ) we have E mb (( 0 , 1 ) Q , < ) �∼ = E mb ([ 0 , 1 ] Q , < ) . (SETTOP 2014) August 21, 2014 12 / 19

  49. The monoid of self-embeddings An application of E mb ( X ) ∼ = E mb ( Y ) ⇒ � P ( X ) , ⊂� ∼ = � P ( Y ) , ⊂� Since P (( 0 , 1 ) Q , < ) �∼ = P ([ 0 , 1 ] Q , < ) we have E mb (( 0 , 1 ) Q , < ) �∼ = E mb ([ 0 , 1 ] Q , < ) . (Comment: but sq P (( 0 , 1 ) Q , < ) ∼ = sq P ([ 0 , 1 ] Q , < ) ) (SETTOP 2014) August 21, 2014 12 / 19

  50. The monoid of self-embeddings Cancellativity commutativity and reversibility of Emb ( X ) (SETTOP 2014) August 21, 2014 13 / 19

  51. The monoid of self-embeddings Cancellativity commutativity and reversibility of Emb ( X ) A monoid M = � M , · , e � is (SETTOP 2014) August 21, 2014 13 / 19

  52. The monoid of self-embeddings Cancellativity commutativity and reversibility of Emb ( X ) A monoid M = � M , · , e � is left reversible ⇔ ∀ x , y ∃ u , v xu = yv (SETTOP 2014) August 21, 2014 13 / 19

  53. The monoid of self-embeddings Cancellativity commutativity and reversibility of Emb ( X ) A monoid M = � M , · , e � is left reversible ⇔ ∀ x , y ∃ u , v xu = yv right reversible ⇔ ∀ x , y ∃ u , v ux = vy (SETTOP 2014) August 21, 2014 13 / 19

  54. The monoid of self-embeddings Cancellativity commutativity and reversibility of Emb ( X ) A monoid M = � M , · , e � is left reversible ⇔ ∀ x , y ∃ u , v xu = yv right reversible ⇔ ∀ x , y ∃ u , v ux = vy If X is a relational structure, a set A ⊂ X will be called embedding-dense , we will write A ∈ EDense ( X ) iff (SETTOP 2014) August 21, 2014 13 / 19

  55. The monoid of self-embeddings Cancellativity commutativity and reversibility of Emb ( X ) A monoid M = � M , · , e � is left reversible ⇔ ∀ x , y ∃ u , v xu = yv right reversible ⇔ ∀ x , y ∃ u , v ux = vy If X is a relational structure, a set A ⊂ X will be called embedding-dense , we will write A ∈ EDense ( X ) iff ∀ g , h ∈ Emb ( X ) ( g ↾ A = h ↾ A ⇒ g = h ) . (SETTOP 2014) August 21, 2014 13 / 19

  56. The monoid of self-embeddings Cancellativity commutativity and reversibility of Emb ( X ) A monoid M = � M , · , e � is left reversible ⇔ ∀ x , y ∃ u , v xu = yv right reversible ⇔ ∀ x , y ∃ u , v ux = vy If X is a relational structure, a set A ⊂ X will be called embedding-dense , we will write A ∈ EDense ( X ) iff ∀ g , h ∈ Emb ( X ) ( g ↾ A = h ↾ A ⇒ g = h ) . Theorem If X is a relational structure, then (SETTOP 2014) August 21, 2014 13 / 19

  57. The monoid of self-embeddings Cancellativity commutativity and reversibility of Emb ( X ) A monoid M = � M , · , e � is left reversible ⇔ ∀ x , y ∃ u , v xu = yv right reversible ⇔ ∀ x , y ∃ u , v ux = vy If X is a relational structure, a set A ⊂ X will be called embedding-dense , we will write A ∈ EDense ( X ) iff ∀ g , h ∈ Emb ( X ) ( g ↾ A = h ↾ A ⇒ g = h ) . Theorem If X is a relational structure, then • E mb ( X ) is cancellative ⇔ P ( X ) ⊂ EDense ( X ) (SETTOP 2014) August 21, 2014 13 / 19

  58. The monoid of self-embeddings Cancellativity commutativity and reversibility of Emb ( X ) A monoid M = � M , · , e � is left reversible ⇔ ∀ x , y ∃ u , v xu = yv right reversible ⇔ ∀ x , y ∃ u , v ux = vy If X is a relational structure, a set A ⊂ X will be called embedding-dense , we will write A ∈ EDense ( X ) iff ∀ g , h ∈ Emb ( X ) ( g ↾ A = h ↾ A ⇒ g = h ) . Theorem If X is a relational structure, then • E mb ( X ) is cancellative ⇔ P ( X ) ⊂ EDense ( X ) • E mb ( X ) is left reversible ⇔ the poset � P ( X ) , ⊂� is atomic (Column A) (SETTOP 2014) August 21, 2014 13 / 19

  59. The monoid of self-embeddings Cancellativity commutativity and reversibility of Emb ( X ) A monoid M = � M , · , e � is left reversible ⇔ ∀ x , y ∃ u , v xu = yv right reversible ⇔ ∀ x , y ∃ u , v ux = vy If X is a relational structure, a set A ⊂ X will be called embedding-dense , we will write A ∈ EDense ( X ) iff ∀ g , h ∈ Emb ( X ) ( g ↾ A = h ↾ A ⇒ g = h ) . Theorem If X is a relational structure, then • E mb ( X ) is cancellative ⇔ P ( X ) ⊂ EDense ( X ) • E mb ( X ) is left reversible ⇔ the poset � P ( X ) , ⊂� is atomic (Column A) • E mb ( X ) is right reversible ⇔ X has the amalgamation property for embeddings (SETTOP 2014) August 21, 2014 13 / 19

  60. The monoid of self-embeddings Cancellativity commutativity and reversibility of Emb ( X ) A monoid M = � M , · , e � is left reversible ⇔ ∀ x , y ∃ u , v xu = yv right reversible ⇔ ∀ x , y ∃ u , v ux = vy If X is a relational structure, a set A ⊂ X will be called embedding-dense , we will write A ∈ EDense ( X ) iff ∀ g , h ∈ Emb ( X ) ( g ↾ A = h ↾ A ⇒ g = h ) . Theorem If X is a relational structure, then • E mb ( X ) is cancellative ⇔ P ( X ) ⊂ EDense ( X ) • E mb ( X ) is left reversible ⇔ the poset � P ( X ) , ⊂� is atomic (Column A) • E mb ( X ) is right reversible ⇔ X has the amalgamation property for embeddings • E mb ( X ) is commutative ⇒ E mb ( X ) is cancellative, left reversible, and right reversible. (SETTOP 2014) August 21, 2014 13 / 19

  61. The monoid of self-embeddings Embeddability of Emb ( X ) into a group (SETTOP 2014) August 21, 2014 14 / 19

  62. The monoid of self-embeddings Embeddability of Emb ( X ) into a group Theorem E mb ( X ) is a (retract of a) group ⇔ P ( X ) = { X } (SETTOP 2014) August 21, 2014 14 / 19

  63. The monoid of self-embeddings Embeddability of Emb ( X ) into a group Theorem E mb ( X ) is a (retract of a) group ⇔ P ( X ) = { X } Theorem Each of the following conditions implies that E mb ( X ) embeds into a group (SETTOP 2014) August 21, 2014 14 / 19

  64. The monoid of self-embeddings Embeddability of Emb ( X ) into a group Theorem E mb ( X ) is a (retract of a) group ⇔ P ( X ) = { X } Theorem Each of the following conditions implies that E mb ( X ) embeds into a group • E mb ( X ) is commutative (SETTOP 2014) August 21, 2014 14 / 19

  65. The monoid of self-embeddings Embeddability of Emb ( X ) into a group Theorem E mb ( X ) is a (retract of a) group ⇔ P ( X ) = { X } Theorem Each of the following conditions implies that E mb ( X ) embeds into a group • E mb ( X ) is commutative • P ( X ) ⊂ EDense ( X ) and P ( X ) is atomic (SETTOP 2014) August 21, 2014 14 / 19

  66. The monoid of self-embeddings Embeddability of Emb ( X ) into a group Theorem E mb ( X ) is a (retract of a) group ⇔ P ( X ) = { X } Theorem Each of the following conditions implies that E mb ( X ) embeds into a group • E mb ( X ) is commutative • P ( X ) ⊂ EDense ( X ) and P ( X ) is atomic • P ( X ) ⊂ EDense ( X ) and X has amalgamation for embeddings (SETTOP 2014) August 21, 2014 14 / 19

  67. The monoid of self-embeddings Embeddability of Emb ( X ) into a group Theorem E mb ( X ) is a (retract of a) group ⇔ P ( X ) = { X } Theorem Each of the following conditions implies that E mb ( X ) embeds into a group • E mb ( X ) is commutative • P ( X ) ⊂ EDense ( X ) and P ( X ) is atomic • P ( X ) ⊂ EDense ( X ) and X has amalgamation for embeddings Proof. Using theorems of Grothendieck, Ore, and Dubreil. (SETTOP 2014) August 21, 2014 14 / 19

  68. The monoid of self-embeddings Everything is possible (SETTOP 2014) August 21, 2014 15 / 19

  69. The monoid of self-embeddings Everything is possible X E mb ( X ) a group E mb ( X ) commutative E mb ( X ) embeddable into a group (SETTOP 2014) August 21, 2014 15 / 19

  70. The monoid of self-embeddings Everything is possible X E mb ( X ) a group E mb ( X ) commutative E mb ( X ) embeddable into a group G Z + + of course (SETTOP 2014) August 21, 2014 15 / 19

  71. The monoid of self-embeddings Everything is possible X E mb ( X ) a group E mb ( X ) commutative E mb ( X ) embeddable into a group G Z + + of course � n ≥ 3 C n + - of course (SETTOP 2014) August 21, 2014 15 / 19

  72. The monoid of self-embeddings Everything is possible X E mb ( X ) a group E mb ( X ) commutative E mb ( X ) embeddable into a group G Z + + of course � n ≥ 3 C n + - of course G ω - + + (SETTOP 2014) August 21, 2014 15 / 19

  73. The monoid of self-embeddings Everything is possible X E mb ( X ) a group E mb ( X ) commutative E mb ( X ) embeddable into a group G Z + + of course � n ≥ 3 C n + - of course G ω - + + G ω ∪ � n ≥ 3 C n - - + (SETTOP 2014) August 21, 2014 15 / 19

  74. The monoid of self-embeddings Everything is possible X E mb ( X ) a group E mb ( X ) commutative E mb ( X ) embeddable into a group G Z + + of course � n ≥ 3 C n + - of course G ω - + + G ω ∪ � n ≥ 3 C n - - + � ω, < � - - - (SETTOP 2014) August 21, 2014 15 / 19

Download Presentation
Download Policy: The content available on the website is offered to you 'AS IS' for your personal information and use only. It cannot be commercialized, licensed, or distributed on other websites without prior consent from the author. To download a presentation, simply click this link. If you encounter any difficulties during the download process, it's possible that the publisher has removed the file from their server.

Recommend


More recommend