The BF Calculus and the Square Root of Negation
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The BF Calculus and the Square Root of Negation Louis H. Kauffman Arthur M. Collings Department of Mathematics, Statistics and Computer Science Independent Researcher University of Illinois at Chicago P.O. Box 114 Chicago, IL USA Red Hook, NY USA Department of Mechanics and Mathematics [email protected] Novosibirsk State University, Novosibirsk, Russia [email protected] Abstract—The concept of imaginary logical values was intro- to BF. Section IV introduces the BF Calculus, stressing the duced by Spencer-Brown in Laws of Form, in analogy to the following important points: square root of -1 in the complex numbers. In this paper, we develop a new approach to representing imaginary values. The • Every consequence in Spencer-Brown's Primary Algebra resulting system, which we call BF, is a four-valued generalization can be represented and formally demonstrated in BF. of Laws of Form. Imaginary values in BF act as cyclic four- • Consequences exist and can be demonstrated in BF that valued operators. The central characteristic of BF is its capacity do no exist in the Primary Algebra. to portray imaginary values as both values and as operators. • All values (real and imaginary) can be viewed as being We show that the BF algebra is an stronger, axiomatically complete extension to Laws of Form capable of representing other both a value and an operation. four-valued systems, including the Kauffman/Varela Waveform • Imaginary values act as cyclic operators, in exact analogy Algebra and Belnap's Four-Valued Bilattice. We conclude by to a clock marked at the four quarter hours. showing a representation of imaginary values based on the Artin Section IV concludes with a proof that the BF algebra is braid group. axiomaically complete based on an extended set of the Bricken Index Terms—imaginary logical values, many-valued logics, indicational notation, Laws of Form, bilattices, distinctions Axioms. Finally, in Section V, we show that each of the four four valued calculi can be represented in BF, and that the BF Algebra is equivalent to a Four Valued Billatice. I. INTRODUCTION II. LAWS OF FORM We reexamine the concept of imaginary logical values, A. Distinction first proposed by George Spencer-Brown [1] and later re- conceptualized by Kauffman and Varela [2]–[4]. Imaginary Laws of Form by Spencer-Brown [1], and the Primary logical values are analogous to i = p 1 in ordinary algebra. Algebra (PA) it describes, is based on the idea of distinction, We introduce a new approach to imaginary− Boolean values represented by the dividing of a space into two regions, one based on the concept of the square root of negation as marked, the second unmarked. In Laws of Form, the mark introduced by Kauffman in 1989 [4], [5] and revived more indicates the marked state, and the empty value indicates recently as a logical calculus that we call BF [7]–[9]. the unmarked state. The step of representing a value by an The reader may recall that the square root of minus one, i, empty space, by the lack of a sign, is motivated by a key can be represented as acting on ordered pairs of real numbers idea: doing so permits the mark to act both as the name by the formula i(a; b) = ( b; a). This suggests a correspond- of a value and as an operation. − ing “logical operator” of the form (a; b) i = ( b; a) where ∼ The Mark O a and b are elements of a Boolean algebra. This is one of the as an <latexit sha1_base64="inF0y6fPfG0yYHOYUi0sum6jyxE=">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</latexit> key ideas behind our construction of BF in this paper, which Operation arXiv:1905.12891v2 [math.LO] 27 Apr 2020 we stress at this point to indicate the close analogy of our I <latexit sha1_base64="inF0y6fPfG0yYHOYUi0sum6jyxE=">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</latexit> work with the extension of the real numbers to the complex <latexit sha1_base64="TTEVi5GImp2Ejf4ZfKOIhBR/OAA=">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</latexit> I =O numbers. <latexit sha1_base64="nCzmnJcRAsaLS/oD7rFdIX+0jkY=">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</latexit> O =I The first section of the paper begins with a brief introduction Fig. 1. Representing a Distinction between Inside (I) and Outside (O) to Laws of Form, to the idea of distinction, and to the notation used by Spencer-Brown. We have emphasized the idea that Consider Figure 1, in which we have drawn a closed circle, values in Laws of Form can be indicated both as names and creating a distinction between inside, I, and outside O. We as operations. In Section III, we introduce several known four- regard the mark as an operator that takes I to O and O valued calculi, which the reader may regard as precursors to I. Then we observe the following: Kauffman’s work was supported by the Laboratory of Topology and I = O; O = I; (1) Dynamics, Novosibirsk State University (contract no. 14.Y26.31.0025 with the Ministry of Education and Science of the Russian Federation). I = O = I; O = I = O; (2) so for any state X we have X = X. The conceptual shift is to designate the inside to be un- , and marked (literally to have no symbol), so that I = . Then from (1) we obtain Calculating in the Primary Arithmetic is based on two = O; O = ; (3) rules, derived from equations (4) and (5) in the prior section, which means we have equated the mark with the outside which may be used to build or simplify expressions. O. From (2), we obtain A1. = . = : (4) A2. = . By identifying the value of the outside with the result of cross- Note that by making A1 and A2 into possible steps that ing from the unmarked inside, Spencer-Brown has introduced transform one expression into another, we have begun the a multiplicity meanings to the mark. The statement = possibility of calculation. In mathematics we take for granted can be interpreted on the left side to mean “cross from the the idea of calculation, but it is exactly in situations where inside” and on the right as “the name of the outside”. there are possible series of transforming steps that calculation The mark itself can be seen to divide its surrounding space arises. into an inside and an outside. When we write , the two marks are positioned mutually outside each other, and Definition 2.2: Two expressions in the Arithmetic are equal we can choose to interpret either mark as a name that refers if one can be obtained from the other by applying A1 and to the outside of the other. We may also interpret two such A2 in a finite series of steps. juxtaposed marks to indicate successive naming of the state Definition 2.3: The two simple expressions are the empty indicated by the mark. In either case we can take expression and the mark . as an instance of the principle that to repeat a name can be identified with a single calling of the name: The primary arithmetic proves extremely useful, and provides a playground, a sandbox for exploring the patterns = : (5) and forms that arise from juxtaposing and nesting expressions At this point we have a single sign representing based on these definitions. Consider the expressions both the operation of crossing the boundary of a distinction and representing the name of the outside of that distinction. , , and . Furthermore, since the mark itself can be seen to make a distinction in its own space, the mark can be regarded as Applying rules A1 and A2 we can that see the first expression referent to itself and to the (outer side) of the distinction that it simplifies to the unmarked state: makes. The two equations (4) and (5) represent these aspects of understanding a distinction