! " # $ = % ∧ & ' π % θ ⊥π ! = & ( =)⇔ ∈ * • + = + ∧ = , • + ⋅ + = . ∧ + + ∧ + + ∧ += ⋅ + + × θ× = × / " 0 ∆ ∆ # $ ∆ = ⋅ ∆ . ' & ∆ 1 ( • , =) ! • , ⊥ ⊥π ∆⊂π ! ! ∆ ∆ ∈ 2π ∈π ∆ 0 3 ∆ * , ∆ % = + θ θ + # 4 ∆ >) ∆ <) ' , 0 $ $ & ' + $$ " 0 6"6 5 ' ! 7 # $ = - = / ⊥ 7 + = + = = + + ∧ + + ∧ + = , ⊥/ + + ∧ ! ,8 3 # $ # 0 83 5 5 5 83 ' -0 83 5 ( 83 83 , 5 $3 3 9 $ . % $ 5 $$ & : 0 3 5 $ 03 & 5 / # $ ; " 83 % = < ' !0 & 99 % ! = < = = <+= ' = < + = ' + ' ' λ= < λ λ ( 0 = < ⋅= ! ' <= ⋅ + ' ' ⋅ > $ > . ? * # # $ =) =) : =) + =) 5 -0 ' A • # $ ≠) 0 =) • -0 3 • 1 0 - $$ ; $$ 83 $ = ≠) =) # $ ≠) =) & • ' ∀ + 3 B, + ⊥ C =) 0 , ∀ + + = % ⊥ + + ∧ + = + ∧ % 1 0 + ⊥ $ % + = + ∧ $$ + ⊥ + = ∧ + ' +λ @ • = ! 2 $0 =) % + 6"6 , % % ( )∧ $$ = = ∧ =) =) & 8 ( • # $ =) • ≠) -0 * # 5 ! -0 6 6A 6 D + =