Metamath Proof Explorer


Theorem arg-ax

Description: A single axiom for propositional calculus discovered by Ken Harris and Branden Fitelson. See: Fitelson,Some recent results in algebra and logical calculi obtained using automated reasoning, 2003 (axiom HF1 on slide 8). (Contributed by Anthony Hart, 14-Aug-2011)

Ref Expression
Assertion arg-ax φψχφψχθχχθφθ

Proof

Step Hyp Ref Expression
1 df-nan θχ¬θχ
2 pm4.57 ¬¬χθ¬φθχθφθ
3 orel2 ¬φχφχ
4 3 com12 χφ¬φχ
5 simpr ψχχ
6 5 a1i χφψχχ
7 4 6 jad χφφψχχ
8 7 com12 φψχχφχ
9 pm3.45 χχχθχθ
10 pm3.45 φχφθχθ
11 9 10 anim12i χχφχχθχθφθχθ
12 jaob χφχχχφχ
13 jaob χθφθχθχθχθφθχθ
14 11 12 13 3imtr4i χφχχθφθχθ
15 8 14 syl φψχχθφθχθ
16 pm3.22 χθθχ
17 15 16 syl6 φψχχθφθθχ
18 2 17 biimtrid φψχ¬¬χθ¬φθθχ
19 18 con1d φψχ¬θχ¬χθ¬φθ
20 df-nan χθ¬χθ
21 20 biimpri ¬χθχθ
22 df-nan φθ¬φθ
23 22 biimpri ¬φθφθ
24 21 23 anim12i ¬χθ¬φθχθφθ
25 19 24 syl6 φψχ¬θχχθφθ
26 1 25 biimtrid φψχθχχθφθ
27 nannan φψχφψχ
28 nannan θχχθφθθχχθφθ
29 26 27 28 3imtr4i φψχθχχθφθ
30 29 ancli φψχφψχθχχθφθ
31 nannan φψχφψχθχχθφθφψχφψχθχχθφθ
32 30 31 mpbir φψχφψχθχχθφθ