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Description: Law for double subtraction of Hilbert space operators. (Contributed by NM, 25-Aug-2006) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | hosubsub |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | hosubsub2 | ||
| 2 | hoaddsubass | ||
| 3 | hoaddsub | ||
| 4 | 2 3 | eqtr3d | |
| 5 | 4 | 3com23 | |
| 6 | 1 5 | eqtrd |