By Assist.prof. Hussein Hadi Abbass University of Kufa\College of Education for girls\ Department of Mathematics Msc_hussien@yahoo.com Hasan Mohammed Ali Saeed University of Kufa\ College of Mathematics and Computer Sciences \Department of Mathematics Has_moh2005@yahoo.com Historical Introduction 1966 1983 • BCK-algebra(Bose, chaudhury, K. Iseki) • BCI-algebra (K. Iseki) • Ideal of BCK-algebra (K. Iseki) • BCH-algebra (Q.P.Hu, X.Li) • Ideal of BCI-algebra (C. S. Hoo) 1991 • Ideal of a BCH-algebra (M. A. Chaudhry) 1996 2010 2011 • Closed ideal of BCH-algebra (M. A. Chaudhry) and (H. Fakhar-ud-din) • Fantastic ideal (A. B. Saeid ) • closed ideal with respect to an element of a BCHalgebra (H. H. Abbass, H.M.A. Saeed) • Closed BCH-algebra with respect to an element (H. H. Abbass, H.M.A. Saeed) أن أغلب األجهزة الرقمية في أنظمة االتصاالت تقوم بنق ل المعلومات على شكل ذبذبات مرمزة بشكل ثنائي أي ان المعلومة ()messageتكون بصيغة 1,0لذلك سوف يكون موضوع الندوة حول الشفرات الثنائية وهذه الشفرات يمكن الحصول عليها من عناصر حق ل غالوا ) GF(2nوعلى سبيل بالرمز لها يرمز ادناه المخطط في الذبذبة المثال 10110 ) GF(2n ينشأ حقل غالوا) GF(2nبأخذ متعددة حدود ) p(xغير قابلة للتحليل (بدائية) primitiveذات درجة nتنتمي الى حلقة متعددة الحدود Z 2 x فيتم انشاء حقل غالوا باستخدامها GF(2n ) Z2 ( x) / p( x) ao a1 ... an1n1 : ao , a1,...,an1 Z2 حيث أن p( ) 0اي ان تكون جذراً لـــ ) p(xأن ) GF(2n وهو حقل توسيع للحقل Z 2ويعتبر هذا الحقل مولد لـ مــثال :أنشئ حقل غالوا ) GF(23 1 n يحتوي على 2nمن العناصر 2من الذبذبات (الشفرات الرقمية ) باستخدام متعددة الحدودp( x) 1 x x Z2 X 3 GF(23 ) a0 a a22 : a0 , a1 , a2 Z 2 وبماأن Z 2 0,1 اذن يمكن ايجاد عناصر غالوا من خالل التعويض عن a0 , a1 , a2 ب 0,1فيكون هناك 2من األحتماالت التي تمثل عناصر ح ق ل غالوا 3 ) GF(23 من وجهة نظر الرياضيات والذي يمثل مولد لشفرات رقمية ثنائية لمصممي األجهزة األلكترونية 3 2 GF(2 ) a0 a a2 : a0 , a1 , a2 Z2 a1 a1 a0 0 0 0 0 0 1 0 1 0 1 0 0 1 0 1 1 1 0 1 1 0 1 1 1 أي أن ) GF(23هو مولد رسائل رقمية ثنائية 0 1 2 1 1 2 2 1 2 الشكل األتي يبين مولد شفرات رقمية shift regesterالذي يمثل الحق ل ) GF(24المولد بواسطة متعددة الحدود 1000 1110 1001 0001 1101 0010 0111 0011 1010 0100 0101 1111 0110 1011 1100 خالل نق ل المعلومات تكون معرضة للتشويش أي بمعنى اخر وجود اشارات دخيلة التي ممكن أن تغير المعلومات المنقولة .لذلك ظهرت الحاجة الى مايسمى الشفرات الكاشفة والمصححة لألخطاء. 0010101010 التشويش التشويش بعد حين صورة مستلمة من احدى االقمار الصناعية قبل تصحيحها وعلى سبيل المثال تقول وكالة ناسا للفضاء األمريكية أنها أرسلت 1969مركبتان فضائيتان ( )Mariners 6,7وأن هاتان المركبتان أرسلتا أكثر من 200صورة لكوكب المريخ كل صورة تحتاج الى ( (5ماليين بت وأن معدل األرسال هو 16200بت في الثانية ترسل الى األرض وأنها قد استخدمت الشفرات الكاشفة والمصححة لألخطاء الصورة التي تم عرضها سابق ا(قبل التصحيح) ( بعد التصحيح ) نعرض الصورة المشوشة التي تم عرضها سابق اً وتظهر الصورة الحقيقية على اليسار www.NASA.gov www.NASA.gov 1.PRELIMINARIES Definition ( 1.1 ) [5, 6] : A BCI-algebra is an algebra (X,*,0), where X is nonempty set, * is a binary operation and o is a constant , satisfying the following axioms: for all x,y, z X: ((x *y) * (x * z)) * (z * y) = 0, (x * (x * y)) * y = 0, x * x = 0, x * y =0 and y * x = 0 imply x = y, Definition ( 1.2 ) [11] : A BCK-algebra is a BCI-algebra satisfying the axiom: 0 * x = 0 for all x X. Definition ( 1.3 ) [10] : A BCH-algebra is an algebra (X,*,0), where X is nonempty set, * is a binary operation and 0 is a constant , satisfying the following axioms: for all x,y, z X: x * x = 0, x * y =0 and y * x = 0 imply x = y, (x*y)*z=(x*z)*y Definition ( 1.4 ) [3, 11, 12] : In any BCH/BCI/BCK-algebra X, a partial order is defined by putting xy if and only if x*y = 0. Proposition ( 1.5 ) [4, 8, 9] : In a BCH-algebra X, the following holds for all x, y, z X, x*0=x, (x * (x * y)) * y = 0, 0 * (x * y) = (0 * x) * (0 * y) , 0 * (0 * (0 * x)) = 0 * x , x y implies 0 * x = 0 * y. Definition ( 1.7 ) [2] : A BCH-algebra X that satisfying in condition if 0 * x = 0 then x = 0, for all xX is called a Psemisimple BCH-algebra. Definition ( 1.8 ) [7] : A BCH-algebra X is called medial if x * ( x * y ) = y , for all x , y X. Definition ( 1.9 ) [2] : A BCH-algebra X is called an associative BCHalgebra if: ( x * y ) * z = x * ( y * z ) , for all x , y , z X. TYPE OF BCH-ALGEBRA BCH-ALGEBRA Psemisimple Medial associative Definition ( 1.10 ) [9] : Let X be a BCH-algebra . Then the set X+ = { x X : 0 * x = 0 } is called the BCA-part of X . Definition ( 1.12 ) [9] : Let X be a BCH-algebra . Then the set med(X) = {x X : 0 * (0 * x) = x} is called the medial part of X . PART OF BCH-ALGEBRA BCH-algebra BCA-part Medial part Theorem ( 1.14 ) [7] : Let X be a BCH-algebra . Then x med(X) if and only if x*y = 0*(y*x) for all x,yX. Definition ( 1.15 ) [9] : Let S be a subset of a BCH-algebra X. S is called a subalgebra of X if x*y S for every x,yS. Definition ( 1.16 ) [2, 7]: Let I be a nonempty subset of a BCH-algebra X. Then I is called an ideal of X if it satisfies: (i) 0I (ii) x*yI and y I imply xI. Definition ( 1.17) [7] : An ideal I of a BCH-algebra X is called a closed ideal of X if 0*xI for all xI. Definition ( 1.18 ) [7] : An ideal I of a BCH-algebra X is called a quasiassociative ideal if 0*(0*x)=0*x, for each x I. Definition ( 1.19 ) [1 ] : Let I be an ideal of X. Then I is called a fantastic ideal of X if (x*y)*zI and zI, then x*(y*(y*x))I, for all x, y, zX. Definition ( 1.19 ) [1 ] : Let I be an ideal of X. Then I is called a fantastic ideal of X if (x*y)*zI and zI, then x*(y*(y*x))I, for all x, y, zX. Proposition ( 1.20 ) [1] : If X is an associative BCI-algebra, then every ideal is a fantastic ideal of X. 2.THE MAIN RESULTS Definition ( 2.1 ): Let X be a BCH-algebra and I be an ideal of X . Then I is called a closed ideal with respect to an element aX (denoted a-closed ideal) if a * ( 0 * x ) I , for all x I. Remark ( 2.2 ): In a BCH-algebra X , the ideal I = {0} is the closed ideal with respect to 0 . Also , the ideal I = X is the closed ideal with respect to all elements of X. Example ( 2.3 ): Let X = {0 ,a ,b ,c }. The following table shows the BCH-algebra on X . * 0 a b c 0 0 a b c a a 0 c b b b c 0 a c c b a 0 Then I={0,a} is closed ideal with respect to( 0 and a) ,Since 0I, If x*yI ,and yI implies xI So I is ideal. 0*(0*0) = 0 I and 0*(0*a) = a I I is 0-closed ideal. Also a*(0*0)=a I and a*(0*a) = 0 I I is a-closed ideal. Definition ( 2.4 ): Let X be a BCH-algebra and aX. Then X is called closed BCH-algebra with respect to a, or a-closed BCH-algebra, if and only if every proper ideal is closed ideal with respect to a. Example ( 2.5 ): Let X={0, 1, 2, 3, 4, 5}. The following table shows the BCH-algebra structure on X. * 0 1 2 3 4 5 0 0 0 0 0 4 4 1 1 0 0 1 4 4 2 2 2 0 2 5 4 3 3 3 3 0 4 4 4 4 4 4 4 0 0 5 5 5 4 5 2 0 I1={0, 1} , I2={0, 1, 2} and I3={0, 1, 2, 3} are all the proper ideals [since if x*yIi and yIi xIi , i=1, 2, 3 ] . I1 is closed ideal with respect to 1 [since 1*(0*x)I1 ,x I1 ] I2 is closed ideal with respect to 1 [since 1*(0*x)I2 ,x I2 ] I3 is closed ideal with respect to 1 [since 1*(0*x)I3 ,x I3 ] Therefore, X is 1-closed BCH-algebra. But X is not 2-closed BCH-algebra, since I1 is not 2-closed ideal[Since(2*(0*1))=2I1 Theorem(2.6) : Let X is a BCH-algebra . If X=X+ (where X+ is a BCApart), then X is 0-closed BCH-algebra . Corollary(2.7) : Every BCK-algebra is 0-closed BCH-algebra. BCK-algebra BCH and BCA-algebra 0-closed BCH-algebra Theorem(2.8) : Let X be a 0-closed BCH-algebra. Then every quasi-associative ideal is closed ideal. Theorem(2.9) : Let X be a 0-closed BCH-algebra. Then every quasiassociative ideal is subalgebra. In 0-closed BCH-algebra Quasi-associative ideal subalgebra Closed ideal proposition(2.10) : Let X be an a-closed BCI-algebra, with aX. If X is an associative BCI-algebra, then every a-closed ideal is a fantastic ideal of X .