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Theorem nic-swap 1245

Description: $-/\$ is symmetric. (Contributed by Jeff Hoffman, 17-Nov-2007.)

**Assertion**
Ref	Expression
nic-swap	$-/\$ $-/\$ $-/\$ $-/\$ $-/\$

**Proof of Theorem nic-swap**
Step	Hyp	Ref	Expression
1		nic-id 1244	. 2 $-/\$ $-/\$
2		nic-ax 1239	. 2 $-/\$ $-/\$ $-/\$ $-/\$ $-/\$ $-/\$ $-/\$ $-/\$ $-/\$ $-/\$ $-/\$
3	1, 2	nic-mp 1237	1 $-/\$ $-/\$ $-/\$ $-/\$ $-/\$

Colors of variables: wff set class

Syntax hints: $-/\$ wnand 1229

This theorem is referenced by: nic-isw1 1246 nic-isw2 1247 nic-luk1 1257

This theorem was proved from axioms: ax-1 4 ax-2 5 ax-3 6 ax-mp 7

This theorem depends on definitions: df-bi 164 df-an 242 df-nand 1230