Exercises on reductions of programs

  1. K  ≤  {p∣∃y:  Mp(y)↓}K\;\leq\;\{ p \mid \exists y:\;M_p(y){\downarrow} \}
  2. K‾  ≤  {p∣∀y:  Mp(y)↓}\overline{K}\;\leq\;\{ p \mid \forall y:\;M_p(y){\downarrow} \}
  3. K‾  ≤  {p∣∃y:  Mp(y)↑}\overline{K}\;\leq\;\{ p \mid \exists y:\;M_p(y){\uparrow} \}
  4. K‾  ≤  {p∣∀y:  Mp(y)↑}\overline{K}\;\leq\;\{ p \mid \forall y:\;M_p(y){\uparrow} \}
  5. K‾  ≤  {p∣∀y:  Mp(y)=y}\overline{K}\;\leq\;\{ p \mid \forall y:\;M_p(y)=y \}
  6. K‾  ≤  {p∣φp total and injective}\overline{K}\;\leq\;\{ p \mid \varphi_p\text{ total and injective} \}
  7. K‾  ≤  {p∣φp total and non-injective}\overline{K}\;\leq\;\{ p \mid \varphi_p\text{ total and non-injective} \}
  8. K‾  ≤  {p∣Mp(1)↓ ∧ Mp(2)↑}\overline{K}\;\leq\;\{ p \mid M_p(1){\downarrow} \,\wedge\, M_p(2){\uparrow} \}
  9. K  ≤  {p∣∣Dom(φp)∣≥2}K\;\leq\;\{ p \mid |\mathtt{Dom}(\varphi_p)|\geq 2 \}
  10. K‾  ≤  {p∣∣Dom(φp)∣=2}\overline{K}\;\leq\;\{ p \mid |\mathtt{Dom}(\varphi_p)|=2 \}
  11. K  ≤  {p∣∣Im(φp)∣≥2}K\;\leq\;\{ p \mid |\mathtt{Im}(\varphi_p)|\geq 2 \}
  12. K‾  ≤  {p∣∣Im(φp)∣=2}\overline{K}\;\leq\;\{ p \mid |\mathtt{Im}(\varphi_p)|=2 \}
  13. K‾  ≤  {p∣∣Dom(φp)∣=∞  ∧  ∣Im(φp)∣=∞  ∧  Dom(φp)∩Im(φp)=∅}\overline{K}\;\leq\;\{ p \mid |\mathtt{Dom}(\varphi_p)|=\infty\;\wedge\;|\mathtt{Im}(\varphi_p)|=\infty\;\wedge\;\mathtt{Dom}(\varphi_p)\cap\mathtt{Im}(\varphi_p)=\emptyset \}
  14. K  ≤  {⟨p,q⟩∣∃y:  (Mp(y)↓ ∧ Mq(y)↓)}K\;\leq\;\{ \langle p,q\rangle \mid \exists y:\;(M_p(y){\downarrow} \,\wedge\, M_q(y){\downarrow}) \}
  15. K‾  ≤  {⟨p,q⟩∣∃y:  (Mp(y)↓ ∧ Mq(y)↑)}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid \exists y:\;(M_p(y){\downarrow} \,\wedge\, M_q(y){\uparrow}) \}
  16. K‾  ≤  {⟨p,q⟩∣∃y1,y2:  (Mp(y1)↓ ∧ Mq(y1)↑ ∧ Mp(y2)↑ ∧ Mq(y2)↓)}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid \exists y_1,y_2:\;(M_p(y_1){\downarrow} \,\wedge\, M_q(y_1){\uparrow} \,\wedge\, M_p(y_2){\uparrow} \,\wedge\, M_q(y_2){\downarrow}) \}
  17. K  ≤  {⟨p,q⟩∣∣Dom(φp)∩Dom(φq)∣≥2}K\;\leq\;\{ \langle p,q\rangle \mid |\mathtt{Dom}(\varphi_p)\cap\mathtt{Dom}(\varphi_q)|\geq 2 \}
  18. K‾  ≤  {⟨p,q⟩∣∣Dom(φp)∩Dom(φq)∣=2}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid |\mathtt{Dom}(\varphi_p)\cap\mathtt{Dom}(\varphi_q)|=2 \}
  19. K‾  ≤  {⟨p,q⟩∣∣Dom(φp)∣=∣Dom(φq)∣=∣Im(φp)∣=∣Im(φq)∣=1  ∧  ∣Dom(φp)∪Dom(φq)∪Im(φp)∪Im(φq)∣=1}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid |\mathtt{Dom}(\varphi_p)|=|\mathtt{Dom}(\varphi_q)|=|\mathtt{Im}(\varphi_p)|=|\mathtt{Im}(\varphi_q)|=1\;\wedge\;|\mathtt{Dom}(\varphi_p)\cup\mathtt{Dom}(\varphi_q)\cup\mathtt{Im}(\varphi_p)\cup\mathtt{Im}(\varphi_q)|=1 \}
  20. K‾  ≤  {⟨p,q⟩∣∣Dom(φp)∣=∣Dom(φq)∣=∣Im(φp)∣=∣Im(φq)∣=1  ∧  ∣Dom(φp)∪Dom(φq)∪Im(φp)∪Im(φq)∣=2}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid |\mathtt{Dom}(\varphi_p)|=|\mathtt{Dom}(\varphi_q)|=|\mathtt{Im}(\varphi_p)|=|\mathtt{Im}(\varphi_q)|=1\;\wedge\;|\mathtt{Dom}(\varphi_p)\cup\mathtt{Dom}(\varphi_q)\cup\mathtt{Im}(\varphi_p)\cup\mathtt{Im}(\varphi_q)|=2 \}
  21. K‾  ≤  {⟨p,q⟩∣∣Dom(φp)∣=∣Dom(φq)∣=∣Im(φp)∣=∣Im(φq)∣=1  ∧  ∣Dom(φp)∪Dom(φq)∪Im(φp)∪Im(φq)∣=3}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid |\mathtt{Dom}(\varphi_p)|=|\mathtt{Dom}(\varphi_q)|=|\mathtt{Im}(\varphi_p)|=|\mathtt{Im}(\varphi_q)|=1\;\wedge\;|\mathtt{Dom}(\varphi_p)\cup\mathtt{Dom}(\varphi_q)\cup\mathtt{Im}(\varphi_p)\cup\mathtt{Im}(\varphi_q)|=3 \}
  22. K‾  ≤  {⟨p,q⟩∣∣Dom(φp)∣=∣Dom(φq)∣=∣Im(φp)∣=∣Im(φq)∣=1  ∧  ∣Dom(φp)∪Dom(φq)∪Im(φp)∪Im(φq)∣=4}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid |\mathtt{Dom}(\varphi_p)|=|\mathtt{Dom}(\varphi_q)|=|\mathtt{Im}(\varphi_p)|=|\mathtt{Im}(\varphi_q)|=1\;\wedge\;|\mathtt{Dom}(\varphi_p)\cup\mathtt{Dom}(\varphi_q)\cup\mathtt{Im}(\varphi_p)\cup\mathtt{Im}(\varphi_q)|=4 \}
  23. K‾  ≤  {⟨p,q⟩∣Dom(φp)⊆Dom(φq)}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid \mathtt{Dom}(\varphi_p)\subseteq\mathtt{Dom}(\varphi_q) \}
  24. K‾  ≤  {⟨p,q⟩∣Dom(φp)⊂Dom(φq)}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid \mathtt{Dom}(\varphi_p)\subset\mathtt{Dom}(\varphi_q) \}
  25. K‾  ≤  {⟨p,q⟩∣Dom(φp)⊂Dom(φq)⊂Im(φp)}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid \mathtt{Dom}(\varphi_p)\subset\mathtt{Dom}(\varphi_q)\subset\mathtt{Im}(\varphi_p) \}
  26. K‾  ≤  {⟨p,q⟩∣∣Dom(φp)∣=∞  ∧  ∣Dom(φq)∣=∞  ∧  Dom(φp)∩Dom(φq)=∅}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid |\mathtt{Dom}(\varphi_p)|=\infty\;\wedge\;|\mathtt{Dom}(\varphi_q)|=\infty\;\wedge\;\mathtt{Dom}(\varphi_p)\cap\mathtt{Dom}(\varphi_q)=\emptyset \}
  27. K‾  ≤  {⟨p,q⟩∣∣Dom(φp)∣=∞  ∧  ∣Dom(φq)∣=∞  ∧  Dom(φp)∩Dom(φq)=∅  ∧  ∀y:∣Dom(φp)∩{0,…,y}∣>∣Dom(φq)∩{0,…,y}∣}\overline{K}\;\leq\;\{ \langle p,q\rangle \mid |\mathtt{Dom}(\varphi_p)|=\infty\;\wedge\;|\mathtt{Dom}(\varphi_q)|=\infty\;\wedge\;\mathtt{Dom}(\varphi_p)\cap\mathtt{Dom}(\varphi_q)=\emptyset\;\wedge\;\forall y:|\mathtt{Dom}(\varphi_p)\cap\{0,\ldots,y\}|>|\mathtt{Dom}(\varphi_q)\cap\{0,\ldots,y\}| \}