Theorem starvndxnplusgndx

Description: The slot for the involution function is not the slot for the base set in an extensible structure. Formerly part of proof for ressstarv . (Contributed by AV, 18-Oct-2024)

	Ref	Expression
Assertion	starvndxnplusgndx	$$⊢{\mathrm{*}}_{\mathrm{ndx}}\ne {+}_{\mathrm{ndx}}$$

Proof

Step	Hyp	Ref	Expression
1		2re	$$⊢2\in ℝ$$
2		2lt4	$$⊢2<4$$
3	1 2	gtneii	$$⊢4\ne 2$$
4		starvndx	$$⊢{\mathrm{*}}_{\mathrm{ndx}}=4$$
5		plusgndx	$$⊢{+}_{\mathrm{ndx}}=2$$
6	4 5	neeq12i	$$⊢{\mathrm{*}}_{\mathrm{ndx}}\ne {+}_{\mathrm{ndx}}\leftrightarrow 4\ne 2$$
7	3 6	mpbir	$$⊢{\mathrm{*}}_{\mathrm{ndx}}\ne {+}_{\mathrm{ndx}}$$