Theorem chsleji

Description: Subspace sum is smaller than subspace join. Remark in Kalmbach p. 65. (Contributed by NM, 17-Oct-1999) (New usage is discouraged.)

	Ref	Expression
Hypotheses	ch0le.1	$$⊢A\in {\mathbf{C}}_{\mathscr{H}}$$
	chjcl.2	$$⊢B\in {\mathbf{C}}_{\mathscr{H}}$$
Assertion	chsleji	$$⊢A{+}_{\mathscr{H}}B\subseteq A{\vee }_{\mathscr{H}}B$$

Proof

Step	Hyp	Ref	Expression
1		ch0le.1	$$⊢A\in {\mathbf{C}}_{\mathscr{H}}$$
2		chjcl.2	$$⊢B\in {\mathbf{C}}_{\mathscr{H}}$$
3	1	chshii	$$⊢A\in {\mathbf{S}}_{\mathscr{H}}$$
4	2	chshii	$$⊢B\in {\mathbf{S}}_{\mathscr{H}}$$
5	3 4	shsleji	$$⊢A{+}_{\mathscr{H}}B\subseteq A{\vee }_{\mathscr{H}}B$$