Research article

Convergence rates of the modified forward reflected backward splitting algorithm in Banach spaces

  • Received: 28 January 2023 Revised: 12 March 2023 Accepted: 14 March 2023 Published: 22 March 2023
  • MSC : 65K05, 90C25, 90C30

  • Consider the problem of minimizing the sum of two convex functions, one being smooth and the other non-smooth in Banach space. In this paper, we introduce a non-traditional forward-backward splitting method for solving such minimization problem. We establish different convergence estimates under different stepsize assumptions.

    Citation: Weibo Guan, Wen Song. Convergence rates of the modified forward reflected backward splitting algorithm in Banach spaces[J]. AIMS Mathematics, 2023, 8(5): 12195-12216. doi: 10.3934/math.2023615

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  • Consider the problem of minimizing the sum of two convex functions, one being smooth and the other non-smooth in Banach space. In this paper, we introduce a non-traditional forward-backward splitting method for solving such minimization problem. We establish different convergence estimates under different stepsize assumptions.



    In graph theory, graph labeling is an assignment of labels or weights to the vertices and edges of a graph. Graph labeling plays an important role in many fields such as computer science, coding theory and physics [32]. Baca et al. [10] have introduced the definition of an edge irregular total -labeling of any graph as a labeling L:VE{1,2,3,,} in which every two distinct edges fh and fh of a graph G have distinct weights, this means that wL(fh)wL(fh) where wL(fh)=L(f)+L(h)+L(fh). They have deduced inequality which gives a lower bound of tes(G) for a graph G,

    tes(G)max{|E(G)|+23,Δ+12} (1)

    Also, they have introduced the exact value of TEIS, tes(G) for some families of graphs like fan graph Fn and wheel graph Wn,

    tes(Fn)=3n+23
    tes(Wn)=2n+23.

    In [15] authors have proved that for any tree T

    tes(T)=max{k+13,Δ+12},

    where Δ is maximum degree on k vertices. In addition, Salama [26] investigated the exact value of TEIS for a polar grid graph,

    tes(Pm,n)=2mn+23.

    Authors in [1] determined TEIS for zigzag graphs. Also, the exact value of TEIS of the generalized web graph Wn,m and some families has been determined, see [14]. Tilukay et al. [31] have investigated total irregularity strength for a wheel graph, a fan graph, a triangular Book graph and a friendship graph. On the other hand, in [2,3,8,17,20,24,29] the total edge irregularity strengths for hexagonal grid graphs, centralized uniform theta graphs, generalized helm graph, series parallel graphs, disjoint union of isomorphic copies of generalized Petersen graph, disjoint union of wheel graphs, subdivision of star Sn and categorical product of two cycles have been investigated. For more details, see [4,5,6,7,9,11,12,13,16,18,19,21,23,25,27,28,30].

    A generalized theta graph θ(t1,t2,,tn) is a pair of n internal disjoint paths with lengths at least two joined by end vertices where the end vertices are named south pole S and north pole N and ti is the number of vertices in the nth path. Uniform theta graph θ(t,m) is a generalized theta graph in which all paths have the same numbers of internal vertices, for more details see [22].

    In this paper, we have defined a new type of family of graph called uniform theta snake graph, θn(t,m). Also, the exact value of TEIS for some special types of the new family has been determined.

    In the following, we define a new type of graph which is called uniform theta snake graph.

    Definition 1. If we replace each edge of a path Pn by a uniform theta graph θ(t,m), we have a uniform theta snake graph θn(t,m). See Figure 1.

    Figure 1.  Uniform theta snake graph θ(t, m).

    It is clear that for a uniform theta snake graph |E(θn(t,m))|=t(m+1)n and |V(θn(t,m))|=(tm+1)n+1. In this section, we determine the exact value of TEIS for uniform theta snake graph θn(3,3), θn(3,m), θn(t,3), θn(4,m), and θn(t,4).

    Theorem 1. For a uniform theta snake graph θn(3,3) with 10n+1 vertices and 12n edges, we have

    tes(θn(3,3))=4n+1.

    Proof. Since a uniform theta snake graph θn(3,3) has 12n edges and (θn(3,3))=6, then from (1) we have:

    tes(θn(3,3))4n+1.

    To prove the invers inequality, we show that ħ labeling is an edge irregular total for θn(3,3), see Figure 2, and ħ=4n+1. Let ħ=4n+1 and a total ħ labeling α:V(θn(3,3))E(θn(3,3)){1,2,3,,ħ} is defined as:

    Figure 2.  Uniform theta snake graph θ(3, 3).
    α(c0)=1,
    α(cs)=4sfor1sn1
    α(cn)=ħ,
    α(xi,j)={jfor1j3j+1for4j6....j+n1for3n2j3n1,i=1,2,3
    α(xi,3n)=ħ1fori=1,2,3
    α(c0xi,1)=ifori=i1,2,3
    α(cSxi,3S)=4S+ifor1Sn1,i=1,2,3
    α(cSxi,3S+1)=4S+i+1for1Sn1,i=1,2,3
    α(cnxi,3n)={ħ2fori=1ħ1fori=2ħfori=3
    α(xi,jxi,j+1i)={j+i+1for1j2j+i+2for4j5....j+i+nI1for3n5j3n4ħ+i3for3n2j3n1,i=1,2,3.

    It is clear that ħ is the greatest used label. The weights of edges of θn(3,3) are given by:

    wα(c0xi,1)=i+2fori=1,2,3
    wα(cSxi,3S)=12S+i1for1Sn1,i=1,2,3
    wα(cSxi,3S+1)=12S+i+2for1Sn1,i=1,2,3,
    wα(cnxi,3n)={3(ħ1)fori=13ħ2fori=23ħ1fori=3
    wα(xi,jxi,j+1)={3j+i+2for1j23j+i+5for4j5....3j+i+3n4for3n5j3n43ħ+i10forj=3n23ħ+i7forj=3n1,i=1,2,3

    Obviously, the weights of edges are distinct. So α is an edge irregular total ħ labeling. Hence

    tes(θn(3,3))=4n+1.

    Theorem 2. For θn(3,m),m>3 be a uniform theta snake graph. Then

    tes(θn(3,m))=(m+1)n+1.

    Proof. Since |E(θn(3,m))|=3(m+1)n and Δ(θn(3,m))=6. Substituting in (1), we find

    tes(θn(3,m))(m+1)n+1.

    The existence of an edge irregular total ƛ labeling for θn(3,m), See Figure 3, m>3 will be shown, with ƛ=(m+1)n+1. Define a total ƛ labeling β:V(θn(3,m))E(θn(3,m)){1,2,3,,ƛ} for θn(3,m) as:

    Figure 3.  Uniform theta snake graph θ(3, m).
    β(c0)=1,
    β(cs)=(m+1)sfor1sn1
    β(cn)=ƛ
    β(xi,j)={jfor1jmj+1form+1j2m....j+n1form(n1)+1jmn1
    β(xi,mn)=ƛ1fori=1,2,3
    β(c0xi,1)=1fori=1,2,3
    β(cSxi,mS)=(m+1)S+ifor1Sn1,i=1,2,3
    β(cSxi,mS+1)=(m+1)S+i+1for1Sn1,i=1,2,3
    β(cnxi,mn)={ƛ2fori=1ƛ1fori=2ƛfori=3
    β(xi,jxi,j+1)={j+i+1for1jm1j+i+2form+1j2m1....j+i+nform(n1)+1jmn2j+i+n1forj=mn1.

    Clearly, ƛ is the most label of edges and vertices. The edges weights are given as follows:

    wβ(c0xi,1)=i+2fori=1,2,3
    wβ(cSxi,mS)=3(m+1)S+i1for1Sn1,i=1,2,3
    wβ(cSxi,mS+1)=3(m+1)S+i+2for1Sn1,i=1,2,3
    wβ(cnxi,mn)={3ƛ3fori=13ƛ2fori=23ƛ1fori=3
    wβ(xi,jxi,j+1)={3j+i+2for1jm13j+i+5form+1j2m1....3jI+i+3n1form(n1)+1jmn23ƛ+i7forj=mn1,

    It is obvious that the weights of edges are different, thus β is an edge irregular total ƛ labeling of θn(3,m). Hence

    tes(θn(3,m))=(m+1)n+1.

    Theorem 3. Let θn(t,3) be a theta snake graph for t>3. Then

    tes(θn(t,3))=4tn+23.

    Proof. A size of the graph θn(t,3) equals 4tn and Δ(θn(t,3))=2t, then from (1) we have

    tes(θn(t,3))4tn+23.

    We define an edge irregular total ħ labeling for θn(t,3) to get upper bound. So, let ħ=4tn+23 and a total ħ labeling γ:V(θn(t,3))E(θn(t,3)){1,2,3,,ħ} is defined in the following three cases:

    Case 1. 4tn+20(mod3)

    γ is defined as:

    γ(c0)=1,
    γ(cS)=(t+1)Sfor1Sn1
    γ(cn)=ħ
    γ(xi,j)I={ifor1j3,i=1,2,,ti+t+1for4j6,i=1,2,,ti+2(t+1)for7j9,i=1,2,,t......i+(n1)(t+1)for3n5j3n3,i=1,2,,tħ1for3n2j3n,i=1ħfor3n2j3n,i=2,3,,t
    γ(c0xi,1)=1fori=1,2,,t
    γ(cSxi,3S)=2St2S+3for1Sn1,i=1,2,,t
    γ(cnxi,3n)={ħt+2fori=1ħt+ifori=2,3,,t
    γ(cSxi,3S+1)=2St2S+2for1Sn1,i=1,2,,t
    γ(cn1xi,3n2)={{(t+2)nt5fori=1(t+2)nt+i7fori=2,3,,t,n=2,3{(t+1)nt1fori=1(t+1)nt+i3fori=2,3,,t,n2,3
    γ(xi,jxi,j+1)={{t+jfor1j23t+j5for4j55t+j10for7j8......(2n3)t+j5(n2)for3n5j3n4,i=1,2,,tħ3(t+n)+j+5for3n2j3n1,i=1ħ3(t+n)+j+5+2(i2)for3n2j3n1,i=2,3,,t

    Obviously, ħ is the greatest label. The edges weights of θn(t,3) can be expressed as:

    wγ(c0xi,1)=i+2fori=1,2,,t
    wγ(cSxi,3S)=t(4S1)+i+2for1Sn1,i=1,2,,t
    wγ(cSxi,3S+1)=4St+i+2for1Sn1,i=1,2,,t
    wγ(cn1xi,3n2)={2nt+3n2t+ħ+i8forn=2,32nt+2n2t+ħ+i4forn2,3,i=1,2,,t
    wγ(xi,jxi,j+1)={{t+j+2ifor1j25t+j+2i4for4j59t+j+2i6for7j8......(4n5)t+j+2i3n+8for3ni5j3n4,i=1,2,,t3ħ3(t+in)+j+3for3n2j3n1,i=13ħ3(t+in)+j+2i+3for3n2j3n1,i=2,3,,t

    It implies that the edges weights have distinct values. So γ is the desired edge irregular total ħ labeling, ħ=4tn+23. Hence

    tes(θn(t,3))=4tn+23.

    Case 2. 4tn+21(mod3)

    Defineγ as:

    γ(c0)=1,
    γ(cS)=(t+1)Sfor1Sn1
    γ(cn)=ħ
    γ(xi,j)={ifor1j3,i=1,2,,ti+t+1for4j6,i=1,2,,ti+2(t+1)for7j9,i=1,2,,t......i+(n+1)(t+1)for3n5j3n3,i=1,2,,tħ1for3n2j3n,i=1ħfor3n2j3n,i=2,3,,t
    γ(c0xi,1)=1fori=1,2,,t
    γ(cSxi,3S)=2St2S+3for1Sn1,i=1,2,,t
    γ(cnxi,3n)={ħtfori=1ħt+i2fori=2,3,,t
    γ(cSxi,3S+1)=2St2S+2for1ISn1,i=1,2,t
    γ(cn1xi3n2)={{(t+2)nt5fori=1(t+2)nt+i7fori=2,3,,t,n=2,3{(t+1)nt1fori=1(It+I1)nt+i3fori=2,3,,t,n2,3
    γ(xi,jxi,j+1)={{t+jfor1j23t+j5for4j55t+j10for7j8......(2n3)t+j5(n2)for3n5j3n4,i=1,2,,tħ3(t+n)+j+3for3n2j3n1,i=1ħ3(t+n)+j+2(i2)for3n2j3n1,i=2,3,,t

    It is clear that the greatest label is ħ. We define the weights of edges of θn(t,3) as:

    wγ(c0xi,1)=i+2fori=1,2,,t
    wγ(cSxi,3S)=t(4S1)+i+2for1Sn1,i=1,2,,twγ(cnxi,3n)=3ħt+i2for1Sn1,i=1,2,,t
    wγ(cSxi,3S+1)=4St+i+2for1Sn1,i=1,2,,t
    wγ(cn1xi,3n2)={2nt+3n2t+ħ+i8forn=2,32nt+2n2t+ħ+i4forn2,3,i=1,2,,t
    wγ(xi,jxi,j+1)={{t+j+2ifor1j25t+j+2i4for4j59t+j+2i6for7j8......(4n5)t+j+2i3n+8for3n5j3n4,i=1,2,,t3ħ3(t+n)+j+1for3n2j3n1,i=13ħ3(t+n)+j+2(i2)for3n2j3n1,i=2,3,,t

    It is obvious that the edges weights are different. Then

    tes(θn(t,3))=4tn+23.

    Case 3. 4tn+22(mod3)

    γ is defined as follows:

    γ(c0)=1,
    γ(cS)=(t+1)Sfor1Sn1
    γ(cn)=ħ
    γ(xi,j)={ifor1j3,i=1,2,,ti+t+1for4j6,i=1,2,,ti+2(t+1)for7j9,i=1,2,,t......i+(n1)(t+1)for3n5j3n3,i=1,2,,tħ1for3n2j3n,i=1ħfor3n2j3n,i=2,3,,t,
    γ(c0xi,1)=1fori=1,2,,t
    γ(cSxi,3S)=2St2S+3for1Sn1,i=1,2,,t
    γ(cnxi,3n)={ħt+1fori=1ħt+i1fori=2,3,,t
    γ(cSxi,3S+1)=2St2S+2for1Sn2,i=1,2,,t
    γ(cn1xi,3n2)={{(t+2)nt5fori=1(t+2)nt+i7fori=2,3,,t,n=2,3{(t+1)nt1fori=1(t+1)nt+i3fori=2,3,,t,n2,3
    γ(xi,jxi,j+1)={{t+jfor1j23t+j5for4j55t+j10for7j8......(2n3)t+j5(n2)for3n5j3n4,i=1,2,tħ3(t+i)+j+4for3n2j3ni1,i=1ħ3(t+n)+j+2ifor3n2j3n1,i=2,3,,t

    We can see that ħ is the greatest label. For edges weights of θn(t,3), we have

    wγ(c0xi,1)=i+2fori=1,2,,t
    wγ(c0xi,3S)=t(4S1)+i+2for1Sn1,i=1,2,,twγ(cnxi,3n)=3ħt+i1for1Sn1,i=1,2,,t
    wγ(cSxi,3S+1)=4St+i+2for1Sn1,i=1,2,,t
    wγ(cnxi,3n2)={2nt3n2t+ħ+i8forn=2,32nt+2n2t+ħ+i4forn2,3,i=1,2,,t
    wγ(xi,jxi,j+1)={{t+j+2ifor1j25t+j+2i4for4j59t+j+2i6for7j8......(4n5)t+j+2i3n+8for3n5j3n4,i=1,2,,t3ħ3(t+n)+j+2for3n2j3n1,i=13ħ3(t+n)+j+2ifor3n2j3n1,i=2,3,,t

    It clears that the edges weights are i distinct. So γ is the desired edge irregular total ħ labeling, ħ=4tn+23. Hence

    tes(θn(t,3))=4tn+23.

    Theorem 4. For θn(4,m) be a theta snake graph for t>3. Then

    tes(θn(4,m))=4(m+1)n+23.

    Proof. Since |E(θn(4,m))|=4(m+1)n and Δ(θn(4,m))=8, then from (1) we have

    tes(θn(4,m))4(m+1)n+23.

    The existence of an edge irregular total ƛ labeling for θn(4,m), m>3 will be shown, with ƛ=4(m+1)n+23. Define a total ƛ labeling β:V(θn(4,m))E(θn(4,m)){1,2,3,,ƛ} for θn(4,m) in the following three cases as:

    Case 1. 4(m+1)n+20(mod3), i=1,2,3,4

    β is defined as:

    β(cs)={1fors=0(m+1)sfor1sn2ƛ+snforn2sn
    β(xi,j)={jfor1jmj+1form+1j2m....j+n21ƛj+22ƛform(n21)+1jmn2+1formn2+2jm(n1)form(n1)+1jmn1,
    β(c0xi,1)=1fori=1,2,3,4
    β(cSxi,mS)={2cS+i1for1Sn21cS+i4(m+1)forn2sn1ƛ4+ifors=n,i=1,2,3,4
    β(cSxi,mS+1)={2cS+i+1for1Sn2,i=1,2,3,4cS+i4(m+1)+2forn2+1sn1
    β(cnxi,mn)={ƛ3fori=1ƛ2fori=2ƛ1ƛfori=3fori=4
    β(xi,jxi,j+1)={j+i+1for1jm1j+i+2form+1j2m1....j+i+n2forj=m(n21)+12j+i2[nm(n21)+1]form(n21)+2jmn1.

    It is clear that ƛ is the greatest used label. The weights of edges of θn(4,m) are given by:

    wβ(c0xi,1)=i+2fori=1,2,3,4
    wβ(cSxi,mS)={2ms+s+2cS+i1for1Sn21,cS+i+ƛ+(s4)(m+1)n+n21forn2sn13ƛ4+i+snfors=n,i=1,2,3,4
    wβ(cSxi,mS+1)={(2m+1)s+2cS+i+1for1Sn2,2ƛ+sn+cS+i4(m+1)+2forn2sn1i=1,2,3,4,
    wβ(cnxi,mn)={3ƛ+sn3fori=13ƛ+sn2fori=23ƛ+sn13ƛ+snfori=3fori=4
    wβ(xi,jxi,j+1)={3j+i+2for1jm13j+i+4form+1j2m1....3j+i+3n21forj=m(n21)+14j+2ƛ+45+i2[nm(n21)+1]2j+2ƛ+i2[nm(n21)+1]formn2+2jm(n1)form(n1)+1jmn1,

    It is obvious that the weights of edges are different, thus β is an edge irregular total ƛ labeling of θn(4,m). Hence

    tes(θn(4,m))=4(m+1)n+23.

    Case 2. 4(m+1)n+21(mod3), i=1,2,3,4

    β is defined as:

    β(cs)={1fors=0(m+1)sfor1sn2ƛ+snforn2sn
    β(xi,j)={jfor1jmj+1form+1j2m....j+n21ƛj+22ƛform(n21)+1jmn2formn2+1jm(n1)form(n1)+1jmn1,
    β(c0xi,1)=1fori=1,2,3,4
    β(cSxi,mS)={2cS+i1for1Sn21,ƛ7+ifors=n2cS+i4m2forn2+1sn1ƛ6+ifors=n,i=1,2,3,4
    β(cSxi,mS+1)={2cS+i+1for1Sn2cS+i4mforn2sn1,i=1,2,3,4
    β(cnxi,mn)={ƛ5fori=1ƛ4fori=2ƛ3ƛ2fori=3fori=4
    β(xi,jxi,j+1)={j+i+1for1jm1j+i+2form+1j2m1....j+i+n2forj=m(n21)+12j+i2[nm(n21)+1]form(n21)+2jmn1.

    It is clear that ƛ is the greatest used label. The weights of edges of θn(4,m) are given by:

    wβ(c0xi,1)=i+2fori=1,2,3,4
    wβ(cSxi,mS)={2ms+s+2cS+i1for1Sn21,2ƛmn2+(m+1)s+i+15fors=n2cS+i+ƛ+(s4)(m+1)n+n21forn2sn13ƛ4+i+snfors=n
    wβ(cSxi,mS+1)={(2m+1)s+2cS+i+1for1Sn2,i=1,2,3,42ƛ+sn+cS+i4mforn2sn1i=1,2,3,4,
    wβ(cnxi,mn)={3ƛ+sn5fori=13ƛ+sn4fori=23ƛ+sn33ƛ+sn2fori=3fori=4
    wβ(xi,jxi,j+1)={3j+i+2for1jm13j+i+4form+1j2m1....3j+i+3n21forj=m(n21)+14j+2ƛ+45+i2[nm(n21)+1]2j+2ƛ+i2[nm(n21)+1]formn2+2jm(n1)form(n1)+1jmn1,

    It is obvious that the weights of edges are different, thus β is an edge irregular total ƛ labeling of θn(4,m). Hence

    tes(θn(4,m))=4(m+1)n+23.

    Case 3. 4(m+1)n+22(mod3), i=1,2,3,4

    β is defined as:

    β(cs)={1fors=0(m+1)sfor1sn2ƛ+snforn2sn
    β(xi,j)={jfor1jmj+1form+1j2m....j+n21ƛj+22ƛform(n22)+1jm(n21)form(n21)+1jm(n1)form(n1)+1jmn1,
    β(c0xi,1)=1fori=1,2,3,4
    β(cSxi,mS)={2cS+i1for1Sn21,i=1,2,3,4ƛ7+ifors=n2cS+i4m2forn2+1sn1ƛ5+ifors=n
    β(cSxi,mS+1)={2cS+i+1for1Sn21,i=1,2,3,4cS+1+ifors=n2cS+i4m+1forn2+1sn1
    β(cnxi,mn)={ƛ4fori=1ƛ3fori=2ƛ2ƛ1fori=3fori=4
    β(xi,jxi,j+1)={j+i+1for1jm1j+i+2form+1j2m1....j+i+n2forj=m(n21)+12j+i2[nm(n21)+1]+1form(n21)+2jmn1.

    It is clear that ƛ is the greatest used label. The weights of edges of θn(4,m) are given by:

    wβ(c0xi,1)=i+2fori=1,2,3,4
    wβ(cSxi,mS)={2ms+s+2cS+i1for1Sn21,2ƛmn2+(m+1)s+i+15fors=n2cS+i+ƛ+(s4)(m+1)n+n21forn2sn13ƛ3+i+snfors=n
    wβ(cSxi,mS+1)={(2m+1)s+2cS+i+1for1Sn2,i=1,2,3,42ƛ+sn+cS+i4m+1forn2sn1,
    wβ(cnxi,mn)={3ƛ+sn3fori=13ƛ+sn2fori=23ƛ+sn13ƛ+snfori=3fori=4
    wβ(xi,jxi,j+1)={3j+i+2for1jm13j+i+4form+1j2m1....3j+i+3n21forj=m(n21)+14j+2ƛ+45+i2[nm(n21)+1]2j+2ƛ+i2[nm(n21)+1]formn2+2jm(n1)form(n1)+1jmn1,

    It is obvious that the weights of edges are different, thus β is an edge irregular total ƛ labeling of θn(4,m). Hence

    tes(θn(4,m))=4(m+1)n+23

    Theorem 5. If θn(t,4) is theta snake graph for t>3. Then

    tes(θn(t,4))=5tn+23.

    Proof. Since |E(θn(t,4))|=5tn and Δ(θn(t,4))=2t. Substituting in (1), we have

    tes(θn(t,4))5tn+23.

    We define an edge irregular total ħ labeling for θn(t,4) to get upper bound. Let ħ=5tn+23 and a total ħ labeling γ:V(θn(t,4))E(θn(t,4)){1,2,3,,ħ} is defined in the following three cases:

    Case 1. 5tn+20(mod3)

    Defineγ as:

    γ(c0)=1,
    γ(cS)=(t+1)Sfor1Sn1
    γ(cn)=ħ
    γ(xi,j)={ifor1j4,i=1,2,,ti+t+1for5j8,i=1,2,,ti+2(t+1)for9j12,i=1,2,,t......i+(n1)(t+1)for4n7j4n4,i=1,2,,tħ1for4n3j4n,i=1ħfor4n3j4n,i=2,3,,t
    γ(c0xi,1)=1fori=1,2,,t
    γ(cSxi,4S)=3St2S+3for1Sn1,i=1,2,,t
    γ(cnxi,4n)={ħt+2fori=1ħt+ifori=2,3,,t
    γ(cSxi,4S+1)=3St2S+2for1Sn1,i=1,2,,t
    γ(cn1xi,4n3)={{(t+2)nt5fori=1(t+2)nt+i7fori=2,3,,t,n=2,3(t+1)nt+i3fori=2,3,,t,n2,3
    γ(xi,jxi,j+1)={{t+jfor1j23t+j5for4j55t+j10for7j8......(2n3)t+j5(n2)for4n5j4n4,i=1,2,,tħ3(t+n)+j+5for4n2j4n,i=1ħ3(t+n)+j+5+2(i2)for4n2j4n,i=2,3,,t

    It is clear that, ħ is the greatest label. The edges weights of θn(t,4) can be expressed as:

    wγ(c0xi,1)=i+2fori=1,2,,t
    wγ(cSxi,4S)=t(5S1)+i+2for1Sn1,i=1,2,,twγ(cnxi,4n)=3ħt+ifori=1,2,,t
    wγ(cSxi,4S+1)=5St+i+2for1Sn1,i=1,2,,t
    wγ(cn1xi,4n2)={2nt+3n2t+ħ+i8forn=2,32nt+2n2t+ħ+i6forn2,3,i=1,2,,t
    wγ(xi,jxi,j+1)={{t+j+2ifor1j25t+j+2i4for4j59t+j+2i6for7j8......(4n5)t+j+2i3n+8for4n5j4n4,i=1,2,,t3ħ3(t+n)+j+3for4n2j4n1,i=13ħ3(t+n)+j+2i+3for4n2j4n1,i=2,3,,t

    It implies that the edges weights have distinct values. So γ is the desired edge irregular total ħ labeling, ħ=5tn+23. Hence

    tes(θn(t,4))=5tn+23.

    Case 2. 5tn+21(mod3)

    Defineγ as:

    γ(c0)=1,
    γ(cS)=(t+1)Sfor1Sn1
    γ(cn)=ħ
    γ(xi,j)={ifor1j4,i=1,2,,ti+t+1for5j8,i=1,2,,ti+2(t+1)for9j12,i=1,2,,t......i+(n+1)(t+1)for4n7j4n4,i=1,2,,tħ1for4n3j4n,i=1ħfor4n3j4n,i=2,3,,t
    γ(c0xi,1)=1fori=1,2,,t
    γ(cSxi,4S)=3St2S+3for1Sn1,i=1,2,,t
    γ(cnxi,4n)={ħtfori=1ħt+i2fori=2,3,,t
    γ(cSxi,4S+1)=3St2S+2
    for1Sn1,i=1,2,t
    γ(cn1xi,4n3)={{(t+2)nt5fori=1(t+2)nt+i7fori=2,3,,t,n=2,3{(t+1)nt1fori=1(t+1)nt+i3fori=2,3,,t,n2,3
    γ(xi,jxi,j+1)={{t+jfor1j33t+j5for5j75t+j10for9j11......(2n3)t+j5(n2)for4n7j4n5,i=1,2,,tħ4(t+n)+j+3for4n3j4n1,i=1ħ4(t+n)+j+2(i2)for4n3j4n1,i=2,3,,t

    It is clear that the i greatest label is ħ. We define the weights of edges of θn(t,4) as:

    wγ(c0xi,1)=i+2fori=1,2,,t
    wγ(cSxi,4S)=t(5S1)+i+2for1Sn1,i=1,2,,twγ(cnxi,4n)=3ħt+i2for1Sn1,i=1,2,,t
    wγ(cSxi,4S+1)=5St+i+2for1Sn1,i=1,2,,t
    wγ(cn1xi,4n3)={3nt+3n2t+ħ+i8forn=2,33nt+2n2t+ħ+i6forn2,3,i=1,2,,t
    wγ(xi,jxi,j+1)={{t+j+2ifor1j35t+j+2i4fori5j79t+j+2i6for9j11......(4n5)t+j+2i3n+8for4n7j4n5,i=1,2,,t3ħ4(t+n)+j+1for4n3j4n1,i=13ħ4(t+n)+j+2(i2)for4n3j4n1,i=2,3,,t

    It is obvious that the edges weights are different. Then

    tes(θn(t,4))=5tn+23.

    Case 3. 5tn+22(mod3)

    Defineγ as:

    γ(c0)=1,
    γ(cS)=(t+1)Sfor1Sn1
    γ(cn)=ħ
    γ(xi,j)={ifor1j4,i=1,2,,ti+t+1for5j8,i=1,2,,ti+2(t+1)for9j12,i=1,2,,t......i+(in1)(t+1)for4n7j4n4,i=1,2,,tħ1for4n3j4n,i=1ħfor4n3j4n,i=2,3,,t,
    γ(c0xi,1)=1fori=1,2,,t
    γ(cSxi,4S)=3St2S+3for1Sn1,i=1,2,,t
    γ(cnxi,4n)={ħt+1fori=1ħt+i1fori=2,3,,t
    γ(cSxi,4S+1)=3St2S+2for1Sn2,i=1,2,,t
    γ(cn1xi,4n3)={{(t+2)nt5fori=1(t+2)nt+i7fori=2,3,,t,n=2,3{(t+1)nt1fori=1(t+1)nt+i3fori=2,3,,t,n2,3
    γ(xi,jxi,j+1)={{t+jfor1j33t+j5for5j75t+j10for9j11......(2n3)t+j5(n2)for4n7j4n5,i=1,2,tħ4(t+n)+j+4for4n3j4n1,i=1ħ4(t+n)+j+2ifor4n3j4n1,i=2,3,,t

    We can see that ħ is the greatest label. For edges weights of θn(t,4), we have:

    wγ(c0xi,1)=i+2fori=1,2,,t
    wγ(c0xi,4S)=t(5S1)+i+2for1Sn1,i=1,2,,twγ(cnxi,4n)=3ħt+i1for1Sin1,i=1,2,,t
    wγ(cSxi,4S+1)=5St+i+2for1Sn1,i=1,2,,t
    wγ(cnxi,4n3)={2nt3n2t+ħ+i8forn=2,32nt+2n2t+ħ+i6forn2,3,i=1,2,,t
    wγ(xi,jxi,j+1)={{t+j+2ifor1j35t+j+2i4for5j79t+j+2i6for9j11......(4n5)t+j+2i3n+8for4n7j4n5,i=1,2,,t3ħ4(t+n)+j+2for4n3j3n1,i=13ħ4(t+n)+j+2ifor4n3j4n1,i=2,3,,t

    It is obvious that the edges weights are distinct. So γ is the desired edge irregular total ħ labeling, ħ=5tn+23. Hence

    tes(θn(t,4))=5tn+23.

    The previous results lead us to introduce the following conjecture for a general case of a uniform theta snake graph θn(t,m).

    The previous results lead us to introduce the following conjecture for a general case of a uniform theta snake graph θn(t,m).

    Conjecture. For uniform theta snake graph θn(t,m), n2,t3,andm3 we have

    tes(θn(t,m))=(m+1)tn+23.

    In the current paper, we have defined a new type of a family of graph called uniform theta snake graph, θn(t,m). Also, the exact i value of TEISs for θn(3,3), θn(3,m) and θn(t,3) has been determined. Finally, we have generalized for t, m and found TEIS of a uniform theta snake graph θn(t,m) for m3, t3.

    tes(θn(3,3))=4n+1.
    tes(θn(3,im))=(im+1)in+1.
    tes(θn(t,3))=4tn+23
    tes(θn(t,m))=(m+1)tn+23.

    All authors declare no conflict of interest in this paper.

    We are so grateful to the reviewer for his many valuable suggestions and comments that significantly improved the paper.



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